Method for elastic foam

 

(57) Abstract:

The invention relates to the production of flexible foams and can be used in the automotive industry, furniture industry, for the production of sports equipment. Obtaining elastic foam material includes a foaming isocyanatobenzene product of the urethane prepolymer in the presence of latex with a dry matter content of not less than 20 wt.% with the ratio of components 80-20: 20-80, when using vulcanizing groups containing sulfur, thiuram, captax and/or altax, in the following ratio, wt.h.: the urethane prepolymer 80-20 specified latex 20-80, sulfur 0,03-0,24, thiuram of 0,005 0,017, captax and/or Altex 0,005-0,05. The method allows to obtain a foam with a higher physical and mechanical properties by obtaining a material with a higher strength polymer base. table 2.

The invention relates to the production of flexible foams and can be used in the automotive industry, furniture industry, for the production of sports equipment.

Known solutions related to ways to obtain foams by foaming isocyanatobenzene prod [2]). In these ways as isocyanatobenzene product, a mixture of a polyhydric alcohol with a molecular mass of 2800-5600 and toluylene diisocyanate or diisocyanate, as a catalyst - octoate tin alone or in composition with other substances, as a blowing agent is water, the emulsifier is a silicone emulsifiers or block copolymer polyorganosiloxane and polyoxyalkylene.

The disadvantages of these methods is the lack of elasticity of the obtained foam, low physical-mechanical characteristics (conditional tensile strength, resistance to long-term and cyclical compression and others).

The closest analogue is the invention according to patent RU 2130466, C 08 G 18/73, 18/16//(C 08 G 18/73, 101:00) [3], publ. 20.05.99, bull. 14. In accordance with the invention is a method of obtaining elastic foam by foaming isocyanatobenzene product in the presence of a catalyst, emulsifier, foaming agent. As isocyanatobenzene product use Polyoxypropylenediamine (urethane prepolymer) with a content of NCO-groups from 2.0 to 4.0 wt.%, as the catalyst, emulsifier, foaming agentii latex to Polyoxypropylenediamine (20-80):(80-20). This method of producing foam is less time-consuming compared to [2], [3] due to fewer components, there is no need for precise dosing, the foam obtained type format" with mesh structure, with a density of 0.25 g/cm3with good elastic properties, is best compared with similar physico-mechanical properties.

However, this method does not allow to obtain a foam with high physical-mechanical properties as the matrix rubber, representing small balls of solid rubber, dispersed in water with the formation of the emulsion, not sewn in chemically foamed polyurethane, and this is only the mechanical interaction of the individual formations of rubber in the polyurethane foam, the rubber is just an inert filler in it, resulting in strength and other physical and mechanical properties is not high enough.

The present invention is to obtain a foam with a higher physical and mechanical properties.

The objective of the invention is solved in a method of producing foam comprising foaming isocyanatobenzene the forming component, which is latex with a dry matter content of not less than 20 wt.%, with a ratio of latex to isocyanatobenzene product (20-80): (80-20); in the method of producing foam is also used vulcanizing the group in the amount of 0.7 to 3.8 wt.h., calculated with respect to the dry residue of the latex per 100 wt.h. latex, thus curing the group includes sulfur, thiuram, captax and/or altax, with the following ratio of components, wt.h.:

Sulfur - 0,5 - 3,0

Thiuram - 0,1 - 0,3

Captax and/or Altex - 0,1 - 0,5

or based on 100 wt.h. the original foam products, wt.h.:

Sulfur - 0,03 - 0,24

Thiuram - 0,005 - 0,017

Captax and/or Altex - 0,005 - 0,05

During the violent reaction of the foaming polyurethane with a large amount of foaming agent addition reaction takes place in vulcanization of rubber with the introduction of vulcanizing groups in the composition of the components, resulting in a fluid grid rubber in the grid foam. Thus there is a net gain structure of the foam, creating a dual grid, which increases the strength of the polymer base. Increasing the strength of the polymer base allows the foam to get more light, for example, for schway grid in the grid foam (for example, in the case of the prototype) this possibility is more lightweight foam is missing, because it becomes unstable and may fall. Obtaining a lighter foam and, therefore, less dense end product will save on initial products to obtain the same volume of the final product.

The use of captax and altaxe as vulcanization accelerators is necessary not only for their intended purpose, but also to deter the activity and regulation catalization properties very strong turama.

In table.1 shows examples of specific performance of the foam in the table.2 - their physical and mechanical properties.

1 shows the composition and properties of the prototype. The method of producing foam in accordance with the prototype involves mixing 50 g Polyoxypropylenediamine - product interaction Laperla-4503 with a diisocyanate with a content of NCO-groups to 2.8 wt.% - 50 g butadienestyrene latex DWHB-70 with a dry matter content of 28 wt.%. The mixing is performed in a vessel with a mechanical stirrer for 3-5 min, then the mixture is then poured into the form and kept in a heating Cabinet at a temperature of 80oC for 60 minutes After SS="ptx2">

The method in accordance with the invention is as follows.

According to example 2 in a vessel with a mechanical stirrer intensively mixed 50 g Polyoxypropylenediamine - product interaction Laperla-3603 with a diisocyanate with a content of NCO-groups to 3.2 wt.% with 0.17 g of natural sulfur or sulfur, obtained by chemical means, of 0.017 g turama, 0.03 g captax, 0.005 g of altaxe. All the obtained composition is intensively mixed with 20 g butadienestyrene latex DWHB-70 with a dry matter content of 28 wt. % within 3-5 minutes, the Prepolymer can be availed in different grades - FULL-TD, SKU-PPL - 65, SKU-PFL - 100. The latex may be taken by a natural or synthetic, such as SCS, DSCI-3, SCA-GP. The mixture is then poured into the form and kept in a heating Cabinet at a temperature of 100-120oC for 120 minutes At this foaming of the prepolymer and the vulcanization of rubber with the formation of the dual mesh material. After cooling, the material is removed from the mold and subjected to testing elasticity, conditional tensile strength, residual strain in compression 50% resistance to long-term compression), fatigue under cyclic compression.

The prepolymer:

FULL-TD: THE 2294-003-50649540-01

WHEN THE 2226-015-10488057-94

Laprol 4503: THE 2226-016-10488057-94

Latex:

DWHB-70: THE 38.303-04-03-90

Apparent density was determined according to GOST 409-68 relative sample mass to its volume.

Ball rebound resilience was determined share of energy returned by the sample, relative to the energy of free-falling pendulum using a pendulum elastomer with brisk hemispherical shape with a radius of 15 mm and the distance from the axis of rotation of the pendulum to the center of the stroke 200 mm

Conditional tensile strength was determined on samples cut from a workpiece, the thickness of 10 mm according to GOST 15873-70.

The residual strain in compression was determined in accordance with GOST 18268-72.

Fatigue under cyclic compression was determined by THE-6-05-1771-76 "Gaskets of flexible molded polyurethane foam" after 5000 cycles of compression at 75% strain.

Examples 3,4 analogous to example 2. The ratio Polyoxypropylenediamine and latex DWHB-70 in mass treatment is 80:20 and 20:80, respectively.

Example 5 same as example 2, only as Polyoxypropylenediamine use the product of the interaction of Laprol 6003 with diisocyanate.

Example 6 is similar to ATA respectively, 0.03 g, 0.005 g 0.005 g to 0.005 g

Example 7 same as example 2, only vulcanizing groups excluded captax and increased the content of altaxe to 0.04,

Example 8 is similar to example 2, only vulcanizing groups excluded altax, and the content of captax is 0.05,

Example 9 same as example 2, as latex uses latex brand SCS-S, of the vulcanizing groups excluded altax and content captax is 0.05,

Examples 10, 11 is similar to example 2, the content of NCO groups in the prepolymer is 2 and 4 wt.% respectively.

Example 12 same as example 2, the content of sulfur vulcanizing group is 0.24 g of curing group excluded altax and content captax is 0.05,

After cooling, the obtained elastic foam is removed from the mold and sent to further processing.

Method for elastic foam including a foaming isocyanatobenzene product of the urethane prepolymer in the presence of latex with a dry matter content of not less than 20 wt. % ratio of components 80-20 : 20-80, characterized in that additionally use vulcanizing the group comprising sulfur, t is 0

The specified latex - 20 - 80

Sulfur - 0,03 - 0,24

Thiuram - 0,005 - 0,017

Captax and/or Altex - 0,005 - 0,05

 

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