Elastic polyurethane foams for the production of upholstered furniture. Fillers for upholstered furniture - interior filling for sofas and armchairs

Polyurethane foams (foamed polyurethanes, polyurethane foam) Are gas-filled, rigid or elastic.

Composition of polyurethane foams

Compositions for the production of polyurethane foams contain isocyanates, hydroxyl-containing oligomers, water, catalysts, emulsifiers, and in some cases fillers, colorants and flame retardants.

Compositions for production flexible polyurethane foams includes simple oligoesters with 750 - 6000 synthesized from oxides alkylene (, propylene), tetrahydrofuran and glycols... Less commonly used complex oligoesters of dicarboxylic acids (adipic, sebacic, amber) and glycols (for example, diethylene glycol). Rigid polyurethane foams are obtained from branched oligoesters based on alkylene and triol oxides (glycerin, trimethylolpropane, etc.) or complex oligoesters based on dicarboxylic acids (adipic, phthalic, etc.) and triols or mixtures thereof with diethylene glycol... The density of the resulting polyurethane foams depends on the ratio and hydroxyl-containing oligomers in the original mixture. With an excess of isocyanates, polyurethane foams contain more urea groups than with a lack of isocyanates, when more urethane groups are formed. Since polyureas have a lower density 1.05-1.23 g / cm 3) than polyurethanes 1.28 g / cm 3), in the first case, polyurethane foams with a lower density are obtained.

Getting polyurethane foams

Polyurethane foams are obtained by interaction di- or polyisocyanates from simple or complex hydroxyl-containing polyesters in the presence of water and catalysts. The blowing agent is carbon dioxide (CO 2)released by the reaction isocyanates with water:

In most cases, catalysts are used tertiary amines and about lovoorganic compounds... In addition to these components, auxiliary substances are introduced into the foam formulations - foam stabilizers, additional foaming agents (for example, freons), dyes, etc.

Polyurethane foams can be divided into two groups:

elastic foams based on linear or slightly branched polyesters;
rigid foams based on highly branched polyesters that form polymers with a higher degree of crosslinking.

The density of the polyurethane foam is adjusted by changing the water content. The more water is introduced, the lower the apparent density of the foam. For example, when obtaining elastic polyurethane foams with an apparent density 32 kg / m 3 about 75% isocyanate groups react with water and only about 25% interacts with the hydroxyl groups of the polyester.

As a result of side reactions during the synthesis of polyurethane foams, along with urethane, other bonds are formed. So, primary amino groupformed during the interaction of isocyanates with water, is capable of reacting with isocyanate group:

The reaction product is a substituted urea, which contains mobile hydrogen at nitrogen and is capable of interacting with isocyanates, as a result of which crosslinking of individual polymer macromolecules can occur at elevated temperatures ("Urea" crosslinking):

Cross-links can also form during the interaction of isocyanate and urethane groups, as well as during the trimerization of isocyanate groups remaining in macromolecules, in:

Interaction isocyanate groups from hydroxyl-containing oligomers and water - competing reactions. The role of the catalyst is to regulate the rate of the above reactions. In this case, the evolution of gas and the growth of polymer molecules should occur at such rates that the gas remains in the polymer, and the formed foam would be strong enough and would not fall off.

Most often as catalysts apply tin compounds (oleate and octoate, dibutyltin salts, etc.), regulating the reaction of formation of urethane units, and tertiary amines (triethylamine, triethanolamine, dimethylbenzylamine, etc.), catalyzing the reactions of the formation of a three-dimensional structure and the release of carbon dioxide. In practice, a catalytic mixture is used consisting of a tin compound and one or more amines. The polyurethane composition can also be foamed low boiling liquidsusually freons.

The chemistry of the formation of flexible and rigid polyurethane foams is the same. Rigid foams differ from elastic foams in that they consist of polymers with a large number of cross-links. In rigid polyurethane foams, the average "molecular weight" of a structural unit per one network branching point is 400 - 700 , in elastic polyurethane foams - 2500-20 000 ... Therefore, compositions for the production of flexible polyurethane foams do not contain trifunctional hydroxyl-containing oligomers (or contain them in small amounts), and also contain less tertiary amines.

An obligatory component of the composition is emulsifier, which promotes a high degree of dispersion of components in the mass and plays the role of foam stabilizer at the moment of foaming. To do this, use sulfoalcohols, sulfonic acids, organosilicon liquids, etc. Some stabilizers (for example, paraffinic hydrocarbons, organosilicon liquids) determine nature (open or closed) and size of pores formed.

Used as antimony trioxide, trichloroethyl phosphate, powder, etc. Most organic dyes are suitable for coloring polyurethane foams. Fill polyurethane foams with talc, expanded clay, fibers of various nature.

Polyurethane foams produce by foaming the composition with gasesreleased as a result of reactions between the components of the initial mixture (see above), or using low boiling liquids... Since a significant amount of heat is released during the formation of polyurethane foam according to the first method, the internal elephant of large-sized products can be charred. Therefore, the first method is applicable only for the manufacture of products of small thickness.

In the second method, the released heat is spent on the evaporation of a low-boiling liquid, which prevents local overheating and carbonization of polyurethane foams

In industry, polyurethane foams are obtained in two ways:

one-stage;
two-stage.

One-step method for the production of polyurethane foams

In a one-step method, all components - diisocyanate, polyester, water, catalyst, stabilizer, emulsifier - are placed in a mixer at the same time and mixed in a reaction apparatus with a stirrer. Foaming occurs immediately, the rise of foam begins in about 10 seconds and ends in 1-2 minutes. The final curing of the foam lasts from several hours to several days.

Two-stage (prepolymer) method for producing polyurethane foams

In a two-stage (prepolymer) method for the production of polyurethane foams, the diisocyanate is first reacted with an oligoester (polyester), and the resulting prepolymer is then converted into polyurethane foam by mixing with water or an amine. The production of polyurethane foam products is carried out according to a continuous or periodic scheme (by pouring into paper forms), as well as by spraying.

Elastic polyurethane foams

Elastic polyurethane foams produced on the basis of complex and simple polyesters. Their most common representative is foam rubber... The raw material for its production is complex polyester based on adipic acid, diethylene glycol and small quantities trimethylolpropane, mix toluylene-2,4- and toluene-2,6-diisocyanates (65: 36 ) as well as water.

Technological process obtaining foam rubber in a block way (Fig. 1) consists of the stages of raw material preparation, polyurethane foaming, manufacturing, aging and processing of foam blocks.

Preparation of raw materials consists in the preparation of an activator mixture. The mixture is prepared in mixers 3 in which from intermediate tanks 1 across measurer 2 feed catalyst (dimethylaniline), emulsifier (sodium salts of sulfonic acids), pore regulating additive (paraffin oil), and water.

Cooked activator mixture, complex polyester and mix toluene diisocyanatescontinuously injected into mixing head of the UBT-65 machine (4 ). The resulting mixture through the drain pipe is fed in a thin stream to a continuously moving paper form, in which foam is formed.

Foaming takes place without heat supply and ends in about 1 minute. The mold with foam is transported by transport through a tunnel with strong ventilation, where gases are released intensively from the foam. When exiting the tunnel, the shape falls on roller conveyor 5 from which it enters drying chamber 6 and then in car 7 for cutting blocks. Blocks stack stacker 8 on shelves 9 and transmitted to chamber 10 for ripening. In this case, the reactions between the components of the foam end, the foam cures and acquires the required strength. Aging lasts about 12-24 hours with continuous blowing of the blocks with air at room temperature.Finished blocks are processed for cutting machines 11 in sheets and packed.

Some properties of polyurethane foams depending on the composition of the composition (I-IV) are given below:

Composition of the composition, in mass parts	I	II	III	IV
Polyester	100	100	100	100
Toluene diisocyanate	45	39	39	31
Water	6,0	5,0	2,5	1,8
Catalyst	1,0	1,0	0,5	0,5
Emulsifier	4,2	2,0	1,0	1,0

The main physical and mechanical indicators of elastic polyurethane foams of the above compositions:

Physical and mechanical properties of flexible polyurethane foams	I	II	III	IV
Apparent density, kg / m 3	25	34	50	59
Breaking stress, MPa in tension	0,34	0,17	0,20	0,21
Breaking stress, MPa in compression (with a bend of 25%)	0,0055	0,0062	0,011	0,013
Elongation at break, %	398	450	400	350

Elastic polyurethane foams have high warmly- and sound insulation performance, good dielectric and shock absorption properties. They are capable of sticking to wood, metals, paper, textiles, etc. Elastic polyurethane foams based on polyester have a higher strength when stretched, tenacity to oxidative aging, exposure to oils and solvents, but less elasticity and frost resistance and less resistance to aging in wet conditions than flexible polyurethane foams based on polyethers.

Properties flexible polyurethane foams domestic brands *

Index	PPU-E	PPU-ET	PPU-EM-1
Apparent density, kg / m 3	25 – 60	30 – 40	30 -50
Tensile strength, Mn / m 2 (kgf cm)	0,12 (1,2)	0,1 (1,0)	0,11-0,13 (1,1 -1,3)
Relative extension, %	150	100	150 – 170
Rebound elasticity, %	15	15	20 – 40
Relative permanent deformation at 50% compression for 72 hours at 20 ° C, %	10	15	10
Compressive stress at 40% deformation (kgf / cm 2)	0,0025 – 0,0075 (0,025 – 0,075)	0,003 – 0,01 (0,03 – 0,1)	0,004 – 0,01 (0,04 – 0,1)
Application temperature, ° С	from -15 to 100	from -20 to 100	from -50 to 100
Weight loss on combustion (fire tube method)	—	22	—
Sound absorption coefficient at 250 Hz	0,35	0,36	—
at 1000 hz	0,80	0,85	—
at 4000 Hz	0,75	0,80	—

Elastic closed cell foams are used for the manufacture of float products, mechanical supports, thermal insulation for operation at low (liquid nitrogen) and relatively high (up to 120 ° C) temperatures. Open cell foam is used to make sponges, cushions, seats, soundproofing materials, and more.

More and more applications are found integral polyurethane foamshaving a dense surface film and a foamed core, and the entire product is formed in one pouring cycle.

Rigid polyurethane foams

Rigid polyurethane foams are obtained mainly by pouring and spraying methods. According to the first method, the process is carried out “as follows.

At elevated temperature and stirring, a mixture of polyester with catalyst, emulsifier and water is prepared. After exposure at 30 ° C during 20-30 minutes add to the mixture toluene diisocyanate and mix the mass for 1-2 minutes.

In this case, the temperature of the mass increases by 5-10 ° C, it increases and partial foaming occurs. Then the mass is poured into restrictive molds corresponding to the configuration of the products. Foaming continues 30-35 minutes.

During this time, the form is filled with foam, which acquires the necessary and cellular structure. For obtaining polyurethane foams by spraying to the surface various materials a portable small-sized unit is used, which consists of heated containers for components, gear pumps and a spray gun with a stirrer. The thickness of the sprayed layer is 5-50 mm, apparent density - from 35 before 200 kg / m 3.

Physical and mechanical properties of some brands of rigid polyurethane foams based polyesters (products of the interaction of diacids with polyhydric alcohols containing free hydroxyl and carboxyl groups) and diisocyanates (mixtures toluene-2,4 and toluene-2,6-diisocyanates) are given below:

Apparent density, kg / m 3	60	100	200
Breaking stress in compression, MPa	0,20	0,78	2,45
Impact strength, kJ / m 2	0,48	0,39	0,59
Thermal conductivity coefficient, W / (m K)	0,024	0,031	0,057
Dielectric loss tangent at 10 10 Hz	1,05	1,1	1,23
Shrinkage (linear) in 24 hours,%	0,6	0,3	0,5
Upper limit of operating temperatures, ° С	100	130 – 150	170
Water absorption in 24 hours, kg / m 2	0,2	0,1	0,1

Rigid polyurethanes are characterized by good dimensional stabilityhave high warmly- and sound insulation performance... They steady to the action of boiling water, gasoline, kerosene, lubricating oils, aqueous solutions of salts, ethyl alcohol, etc. Styrofoam easy to clean with soapy water; they resist mold and decay. Rigid polyurethane foams have good electrical insulation properties. In addition, they exhibit high (glass fiber, glass mats, etc.).

Properties of rigid polyurethane foams of domestic brands *

Index	PU-101	PU-101T	PPU-3S	PPU-304N
Apparent density,kg / m 3	100 – 200	150 – 250	50	30-50
Strength,Mn / m 2 (kgf / cm 2) not less in compression	1,0 – 1,9 (10 – 19)	2,0 – 4,2 (20 – 42)	0,25 (2,5)	0,15 – 0,5 (1,5 – 5)
bending	0,8 – 1,5 (8 – 15)	1,5 – 3,5 (15 – 35)	0,2 (2)	0,2 – 0,9 (2 – 9)
Impact strengthkJ / m 2 orkgf cm / cm 2 , not less	0,4	0,5 – 0,8	0,6	0,4 – 0,6
Coefficient of thermal conductivity, w / (m K)	0,031 – 0,035	0,033 – 0,047	0,033 – 0,038	0,023 – 0,035
*Kcal / (m · h · ° С)*	0,027 – 0,030	0,028 – 0,040	0,028 – 0,033	0,02 – 0,03
Water absorption in 24 hours, %, no more	0,3	0,3	0,3	0,3
Application temperature, ° C	from -50 to 150	from -60 to 200	from -60 to 60	from -60 to 100
Dielectric constant at 10 10 Hz	1,1 – 1,2	1,1 – 1,3	—	—
Dielectric loss tangent at 10 10 Hz	0,0015	0,0016 – 0,0020	—	—

* source - Encyclopedia of Polymers, ed. V.V. Kabanova 1974, volume 2, p. 567.

Polyurethane foams are used to fill gaps in concrete structures and cavities in the manufacture of doors and window frames, to finish caps, radars, tropical helmets, bearing planes and aircraft cabins, etc.

Bibliography:
Vanderberg E. Plastics in industry and technology. M., mechanical engineering, 1964.196 p.
Dombrow B.A.Polyurethanes. Moscow, Goskhimizdat, 1961.152 p.
Lafengauz A: P., Yuoicheva E. Ya. - In the book: Polyfoam. M., Oborongiz, 1960, p. 117;
Pavlov V.V., Goryachev M, S, Durasova T.F. Ibid, p. 131.
Korshak V.V., Frunze G.M. Synthetic heterochain polyamides. M., publishing house of the Academy of Sciences of the USSR, 1962.523 p.
Kuznetsov E, V., Prokhorova I, Ya. Album of technological schemes for the production of polymers and plastics based on them. Ed. 2nd. M., Chemistry, 1975A74 p.
Losev I. Ya. Trostyanskaya EB Chemistry of synthetic polymers. Ed. 2nd. M., Chemistry, 1971.615 p.
Nikolaev A.F. Synthetic polymers and plastic materials based on them. Ed. 2nd, M. ~ L., Chemistry, 1966.768 p.
Saunders J.H., Frisch K./S. Chemistry of polyurethanes. Per. from English / Ed. X. M. Entelis. M., Chemistry, 1968.470 p.
Kercha Yu. Yu. Physical chemistry of polyurethanes. Kiev, Naukova Dumka, 1979, 220 p.
Berlin A. A., Shutov F. A. Reinforced gas-filled plastics. M., Chemistry, 1980.192 p.
Composite materials based on polyurethanes. Per. from English / Ed. F.A. Shutova. Moscow, Chemistry, 1982.214 p.
Dementyev A.G., Tarakanov OG Structure and properties of foam plastic. M., Chemistry, 1983.208 p.
Berlin A.A., Shutov F.A.Polymers based on reactive oligomers M., Chemistry, 1977, 116 p.

(in the mattress) - polymer material with a gas-filled structure, in which more than 85% of the volume is occupied by air. Depending on the parameters of the polymerization reaction, various types of polyurethane foam (PUF) are obtained, from hard plastics to soft foam compounds. In the furniture industry, flexible polyurethane foam of varying degrees of rigidity is used.

Mattresses based on this material differ in different rigidity (depending on density), durability and environmental safety.

The history of springless polyurethane foam mattresses and its use in the furniture industry

PPU was originally synthesized in 1937 at IG Farben's laboratory in Leverkusen. There, the German chemist Otto Bayer discovered both forms of this substance: both rigid and elastic. Immediately recognizing the commercial potential of the material, as well as the wide range of applications, Bayer began to actively disseminate information and offer manufacturers this substance as a filler for upholstered furniture... However, the Second world War prevented the spread of a springless polyurethane foam mattress in those years, and it became widespread already in the sixties.

What is a polyurethane foam mattress in a sofa?

PU foam can be used in the manufacture of mattresses in two versions:

	As the main material of which the mattress is made. In this case, the product is a structure of one or more polyurethane foam layers of varying degrees of rigidity. Such a mattress is distinguished by a sufficiently high level of comfort, as well as perfect silence during operation: the springless solution eliminates any creaks and noises. In addition, the product is highly elastic and durable.
	As an element of a complex mattress structure. A common solution is to use a PU foam interlayer as an outer lining spring block... In this case, the PU layer provides additional comfort and softness. It also significantly increases the durability of the product.

Modern mattresses made of polyurethane foam (or with polyurethane foam) are completely environmentally friendly, do not have foreign odors and are extremely durable.

Types of polyurethane foam used in mattresses and their features

First of all, it should be noted that PUFs of various density are used.

The most popular are 35 kg / m3. (more expensive and hard and elastic) and 25 kg / m3 (most common in sofas, medium hardness).

The degree of rigidity of the product depends on the density (the higher the density, the heavier and tougher the mattress), as well as its endurance. By increasing the rigidity, we increase the permissible load.

With a density of 25 kg / cubic meter. the maximum load is 100 kg per berth, while 35 kg / m3. already increases the limit to 130 kg.

The following types of PPU are used:

Standard - no modifications, with a density of 25 to 35 kg / m3.
Increased rigidity - with the addition of polymers, increasing the density. Used to create hard beds.
Soft and super soft - made from modified raw materials with the addition of special substances that soften the foam. For those who like a softer bed.
Latex polyurethane foam or “with memory” is soft, but its main feature is “memorizing” the shape of the body by reducing elasticity. It does not straighten instantly, but keeps its shape, thereby allowing you to achieve maximum comfort.

Polyurethane foam mattress in the sofa: reviews

The owners of these mattresses note that the products do not have foreign odors, are light enough (therefore it is not difficult to move them, put them, etc.), and are also very comfortable. At the same time, many owners note the durability of the product: it retains its elasticity and original properties for a long period of time.

LLC "RIF-Amethyst" is engaged in the production of many synthetic materials, including polyurethane foam. We actively accept orders for polyurethane foam for furniture, meeting the highest requirements of domestic manufacturers. Our company produces several types of polyurethane foam, serving the wide demand for PU foam of various physical and chemical characteristics.

Advantages of polyurethane foam for furniture

Polyurethane foam is used in many industries and there are specific requirements for each application. It has received such wide distribution due to its special characteristics, a unique combination of which allows achieving very high results. Flexible polyurethane foam for furniture has the following features:

High levels of breathability.
Good moisture exchange and heat retention.
Light weight polyurethane foam products.
Relatively low manufacturing cost.

Thanks to these characteristics, polyurethane foam has become one of the most convenient and profitable materials for any industry, including furniture.

According to its physical and chemical properties, all polyurethane foam for upholstered furniture can be divided into several main types, which, in turn, can also be divided into subspecies with more accurate characteristics.

Types of PPU

The following types of polyurethane foam can be cited as an example:

Standard PPU (ST);
Polyurethane foam with increased rigidity (EL);
Rigid PU foam (HL);
Soft polyurethane foam or with increased softness (HS);
Highly elastic polyurethane foam (HR *);
Highly resilient fireproof polyurethane foam (CMHR).

These types of polyurethane foams are used to make backs, seats, mattresses and other products for the furniture industry. All types of materials listed above differ from each other in their properties. These properties affect the most important indicator - the load that can be exerted on the product. The softer the material, the less stress it is ready to endure. Stiffer or more elastic types of PU foam can withstand loads of more than 120 kilograms. Right choice material for the product is a guarantee of its long service life.

Block and molded polyurethane foam

There are two main ways to produce PU foam: in blocks and by molding. Block polyurethane foam is widely used and is used mainly for typical solutions. In contrast, molded polyurethane foam for furniture is produced for both simple and complex parts. It is poured into special molds, and the result is an element made of polyurethane foam and exactly corresponding to the dimensions of the blank of the future furniture element.

Special types of polyurethane foam

Polyurethane foam is special synthetic material, the invention of which was a real breakthrough for the industry. Of course, a lot of scientific research is carried out annually, which are aimed at the invention of new types of polyurethane foam, which will be able to solve the still unanswered problems. Today there are already such special types PPU as fireproof polyurethane foam, resistant to fire, PPU memory foam, which is distinguished by the characteristics of increased comfort and others. Do you want to use special materials to manufacture your furniture? Contact us to find out what kind of PUF better fit for a new product.

Order the production of polyurethane foam for furniture

You still have questions about which better materials to use to make a new batch of furniture? Would you like to know more about the possibilities of our production? LLC "RIF-Amethyst" will provide you with all the information about our products and our services, detailing the data in the most convenient form for you.

Are you interested in the opportunity to order the production of polyurethane foam for upholstered furniture? In this case, we are ready to offer you our services. For many years we have been serving domestic furniture factories and will be happy to offer our services to you. To place an order for the production of polyurethane foam for furniture, just call the duty manager of RIF-Ametist LLC. He will take the order and answer all your questions. After discussing the details of your project, we can tell you the exact cost and production time.

Nikitina Svetlana Yurievna OJSC "VPKTIM".
Director of the Center for Engineering, Technical and Technological Support of Enterprises

Polyurethanes were first obtained in Germany in the late 30s of the XIX century. In the development of polyurethane elastomers, Bayer chemists have produced end-products with unwanted gas bubbles. Then, already as a result of a targeted study of the interaction of polyhydric alcohols based on complex or polyethers with multifunctional isocyanates and water, a foam with a cellular structure was obtained. Over time, it has evolved into a multipurpose engineering plastic for mass-use polyurethane foam (PUF).

In the early 1950s, flexible polyester (PE) foams were the first to appear, followed by polyether foams a few years later. In the 60s, with the discovery of rigid foams, the field of application of polyurethane foam expanded significantly, and by the end of the 90s they began to be used in almost all industries, with up to 70% of the total volume of elastic polyurethane foam used in the production of mattresses and upholstered furniture. At the same time, various polyurethane foam is used: light and heavy, soft and hard, obtained on the basis of various initial products and formulations of compositions, which make it possible to set a certain apparent density and rigidity, elasticity and the necessary shock-absorbing properties during its manufacture.

According to the manufacturing method, elastic polyurethane foam is divided into molded, when the parts are cast individually, and block, when the final product is large rectangular or cylindrical blocks, which are then cut into blanks.

The apparent density and rigidity of the material is of decisive importance for the use of block elastic polyurethane foam in various parts (zones) of upholstered furniture. Apparent density is the volumetric weight of a porous material. The stiffness of a foam can be viewed as the force with which that material resists deformation. The indicators of the apparent density and stiffness of polyurethane foam are interrelated: the higher the apparent density for a given stiffness, the higher the quality of the foam and the less its fatigue. In practice, this means that a higher load on furniture, the duration and frequency of its deformation must correspond to a higher apparent density. Only under this condition can the desired quality of the soft element be achieved.

It is impossible to give universal recommendations on the selection of the optimal apparent density for various elements of upholstered furniture, since their design and purpose are different, and the layers of the used polyurethane foam have different thicknesses. General recommendations boil down to the following: block elastic polyurethane foam for seats (high and frequent loads) should have the highest apparent density - not less than 28-30 kg / m3; material for armrests and backs (lower loads) - lower, but not less than 23-25 \u200b\u200bkg / m3; for thin floorings, the apparent density should be the highest - not less than 35 kg / m3 for seats and not less than 28 kg / m3 for backrests and armrests, since the thinner the flooring, the higher the degree of deformation at a given pressure (load).

The stiffness of elastic block polyurethane foam can vary widely depending on the initial formulations of the material used: depending on the apparent density, it can be ultra-soft (from 0.5 kPa), soft, standard, hard and very hard (up to 10 kPa). Block elastic polyurethane foam of increased softness is used in furniture in combination with other flooring materials in the form of sheets of small thickness, for example, instead of batting; rigid - like a material that replaces, for example, springs.

The elasticity of the block PPU is determined by the size of the area of \u200b\u200bthe hysteresis loop when applying and removing a load. The smaller this loop, the higher the elasticity, and the faster its recovery after the removal of the deforming force, and vice versa. The wide possibilities of block polyurethane foam for the selection of elasticity during its manufacture allow you to create flooring materials with a wide variety of properties and combine flooring from them that exactly meet all the necessary requirements.

The disadvantage of block polyurethane foam is the loss of some of their original properties after recovery in cases of excessive compression during transportation or storage. This is especially true for block foams with a density below 30 kg / m3. Block polyurethane foam is resistant to aging, and this is, first of all, resistance to prolonged exposure to moisture and temperatures. PU foam based on simple polyesters is more durable in furniture than on the basis of complex ones.

Numerous sanitary and hygienic studies carried out all over the world, including here in Russia, have proved that these materials, made according to a standard recipe, are absolutely safe for human health, and that the light weight, high air permeability, good heat and moisture exchange of the elastic PU foam allows us to accept it as the optimal material for the manufacture of mattresses. But its apparent density should not be lower than 30-35 kg / m3: otherwise, during operation under load, the foam cells are excessively deformed, which significantly reduces air and moisture exchange inside the product.

For complex volumetric soft furniture elements, molded polyurethane foam parts are used, which are manufactured in individual molds with high precision and do not require further refinement. The density of parts made of molded polyurethane foam is much higher than that of parts made of block polyurethane with similar physical and mechanical characteristics: for backs of upholstered furniture not less than 42 kg / m3, and for a more loaded seating area not less than 45-48 kg / m3. And the density of the molded foam for office furniture, due to the small thickness of the soft element and the increased requirements for wear resistance, should be even higher - from 55 to 70 kg / m3.

Due to the high adhesion of polyurethane foam to almost all materials, the molding method makes it possible to simultaneously use embedded parts: metal frames, spring blocks and other structural elements with the formation of a durable connection. Their use simplifies the technological process of making upholstered furniture, since a finished assembly unit is obtained in one operation. But furniture production is characterized by a constant change of assortment and a relatively small serial production. Due to the constant change of molds, the price of which is very high, the cost of parts made of molded polyurethane foam is higher than that of parts made on the basis of block.

Despite the general growth in the production of upholstered furniture, for last years the production of molded foams in Russia is constantly decreasing. This is due to the widespread development of enterprises producing cheaper block polyurethane foam and almost completely covering the needs of upholstered furniture manufacturers. Molded polyurethane foam occupies a very small but permanent niche mainly in the production of high-quality and highly artistic upholstered furniture. But small suppliers of molded polyurethane foam can only produce a very limited range of elements that are simple in shape. Therefore, as in the rest of the world, the future belongs to the larger manufacturers of such parts. But the organization of mobile production of high-quality molded polyurethane foam with a constant change in the range of products is associated with significant capital investments and requires highly qualified personnel.

One of the largest manufacturers of a wide range of high quality molded polyurethane foam is Europlast LLC (Moscow). There are few manufacturers who are ready to supply products to order in small batches. And the main flooring material for upholstered furniture is still block PPU. But in recent years, the volume of production of upholstered furniture has increased, especially furniture of the middle and high price level. There are even enterprises that supply upholstered furniture for export. And the quality of this furniture, which is not immediately noticeable to the consumer, but which he begins to evaluate only after its long-term use, is precisely determined by the quality and correct selection of the PPU used in it.

JSC "VPKTIM" provides services in the areas of production and application

Institute of Furniture (JSC "VPKTIM") has a check and independent examination of the quality of flooring materials in the field of furniture.

Polyurethane foam - one of the most common materials, which is widely used in various fields of human activity. And all this is due to its largely universal characteristics. Belongs to the class of foams and is a foamed base formed by the reaction of two main components polyisocyanate and polyol... Depending on their proportions, you can get different characteristics, cell sizes and the strength of their walls. But to summarize, then polyurethane foams can be divided into two main types that we encounter on a daily basis in our lives.

Elastic polyurethane foam

Elastic polyurethane foam or simple foam rubber - it is mainly used for filling and upholstery of upholstered furniture, mattresses, washcloths, sponges, in clothes, shoes, as a shockproof material for packaging. Average density is usually from 5 to 35 kg / cubic meter and depends on the purpose. For disposable or short-term applications, weaker and lower density flexible polyurethane foams are used. And vice versa, if the service life must be maintained at least 5 - 10 years, they are made more dense and with obligatory opaque cladding. But this is a topic for another forum, we will only consider rigid polyurethane foam for insulation.

Rigid polyurethane foam. Insulation video

Rigid polyurethane foams began to be used in construction relatively recently. But even now we can say what properties these materials will have after 30-50 years of operation. In addition, the results of experiments on accelerated aging are known, confirming the data of laboratory studies. Polyurethane foams are not highly resistant to organic solvents and mineral acids, but they are impervious to water and oil products.

The strength and thermal insulation characteristics of polyurethane foam structures are maintained at temperatures from -80 to +100 degrees. There are brands of polyurethane foam that retain performance at elevated temperatures (up to +150) and at low temperatures (up to -250 degrees).

In Russia, builders use more than 30 brands of rigid polyurethane foams. These materials are used both independently and in combination with each other. The purposes of application are diverse: noise and heat insulation of residential buildings and industrial facilities, insulation of refrigeration equipment, increasing the safety of timber during transportation, hydro and thermal insulation of oil pipelines. Polyurethane foam is resistant to aggressive substances such as gasoline, alcohol, oils, diluted acids, plasticizers. These properties significantly expand the scope of the material.

Equipment for the production of polyurethane foam

Since the technology for the production of polyurethane foam is relatively simple, that is, you need to mix the two main components in the correct proportions polyisocyanate and polyol and spray them with compressed air on the surface to be insulated, then the whole difficulty comes down to their exact dosage. And here equipment for the production of polyurethane foam can be divided into 2 types: low and high pressure.

low pressure equipment for spraying polyurethane foam

This equipment has become more widespread due to its low price, inexpensive maintenance and quick repair. To accurately dose each component, a gear pump is mainly used, which is much more accurate and more powerful than a centrifugal pump. In such equipment for, through a system of dosing and bypass valves, the exact ratio of the supply pressure of polyisocyanate and polyol to the spray gun is set, in which they are mixed and sprayed onto the insulated surface using compressed air with the required flow rate of 350 liters per minute.

Since their component fluidity depends on their temperature, for better mixing and obtaining high-quality sprayed polyurethane foam, it is better to heat polyisocyanate and polyol in special containers up to 60 degrees. But usually, the sellers of the installations offer this as an option for an additional payment.

high pressure equipment for the production of polyurethane foam

The American company Graco is one of the leaders in the production of high-pressure equipment for spraying polyurethane foam and not only. Such equipment is also used to apply any polyurea and liquid rubber for waterproofing, the technology of which includes the mandatory mixing of components under high pressure up to 250 atmospheres.

Due to its versatility and wide range of applications, the cost of such equipment is ten times higher than low. It also uses digital, automatic control of the entire process, high-precision dosing and the necessary heating of raw materials. Although its mass is quite large, about 200 kg, it is compensated by the length of the working hoses, up to 100 meters.

video of equipment for polyurethane foam

insulation with polyurethane foam

Sprayed polyurethane foams surpass all other heat insulators in many respects. For example, they can simultaneously serve as thermal insulation, waterproofing, vapor barrier, and also protect metal from corrosion. Polyurethane foam applied to the metal surface prevents corrosion due to the film formed on the surface of the foam mass. The effectiveness of corrosion protection depends on the grade of polyurethane foam and on the condition of the metal surface.

Polyurethane foam when spraying possesses high adhesion, easily adheres to the surface of any material, is applied very quickly and does not form assembly joints. The adhesion of polyurethane foam to metal, glass, concrete is 2-3 kg / sq. cm, which allows you to perform thermal insulation work without the use of fastening materials.

Resistant to high temperatures and fire. An increase in the fire resistance of polyurethane foams is achieved by introducing chemical additives into its composition - fire retardants. In some cases, it is recommended to apply high density polyurethane foam to a layer of less dense polyurethane foam. Such a two-layer coating is used in facilities with increased requirements for fire resistance. With an increase in the density of polyurethane foam, its flammability decreases.

video of spraying polyurethane foam

Operational period. The durability of a material depends on its resistance to aging, which is defined as the ability to maintain useful characteristics... The ability of polyurethane foam to retain heat is degraded by only 0.3% per year. None of the well-known heaters have such impressive heat-saving properties.

Prolonged exposure to temperature fluctuations and cyclic deformations does not lead to cracks and destruction of the microstructure of this insulation. But direct sunlight, in particular ultraviolet radiation, has a strong effect on unprotected polyurethane foam.

And very often you can hear negative reviews about the use of polyurethane foam as a polyurethane foam when without a protective layer of plaster... Literally a year later, unprotected polyurethane foam turns into dust, while losing all the necessary thermal insulation characteristics.

Polyurethane foam sheets and panels, as well as shells for pipe insulation are produced by pouring it into special forms. For the convenience and quality of installation, the edges are made in the form of special, symmetrical locks so that the joints fit more tightly to each other and a monolithic layer of insulation is obtained.

Now the technology of building budgetary, inexpensive frame houses from OSB sandwich panels insulated with polyurethane foam is gaining popularity. The main advantages are the speed of construction and the price, although the practicality of operation is much less effective than that of more expensive and labor-intensive ones. But each technology will find its buyer.