JPH0485318A - Production of flexible urethane foam - Google Patents

Abstract

PURPOSE:To produce a flexible urethane foam which can retain inherent properties and density even when it is produced by using a smaller amount of a fluorocarbon by using a specified amount of a specified random copolymer as a polyol component in the production of the foam. CONSTITUTION:A process for producing a flexible urethane foam by mixing a polyol composition comprising a polyol, a blowing agent, a catalyst and other adjuvants with an isocyanate and foaming the mixture, wherein said polyol is one containing 10-30wt.% random copolymer of propylene oxide ethylene oxide. The compositional ratio of propylene oxide to ethylene oxide in the random copolymer is desirably 10:90-50:50.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a flexible urethane foam useful for interior materials of automobiles and the like.

[Prior Art] Conventionally, soft urethane films have been used for seat pads as interior materials for automobiles. In the production of this flexible urethane foam, isocyanate is mixed with a polyol composition consisting of a polyol, a blowing agent, a catalyst, and other auxiliary agents to form a urethane polymer, which is foamed by the action of a blowing agent and has a low density. It forms a form with repulsive force. Conventionally, this foaming agent is a combination of water and fluorocarbons. However, recently, consideration has been given to reducing the use of fluorocarbons due to environmental concerns.

When the amount of fluorocarbon is reduced during the production of soft urethane foam, it is conceivable to increase the amount of other blowing agents, such as water, to generate carbon dioxide gas in order to maintain a low density. However, when the amount of water increases, urea bonds are formed due to the reaction between water and isocyanate, increasing the hardness of the foam and reducing its impact resilience. For this reason, the produced foam cannot be used as an automobile seat pad material.

Therefore, in order to prevent a decrease in the hardness and physical properties of the foam and to reduce the amount of fluorocarbon, it is necessary to consider the composition of the main components constituting the urethane.

[Problems to be Solved by the Invention] By the way, in the production of flexible urethane foam, the properties may be affected by the polyurethane produced by the polyaddition reaction between the polyol and isocyanate constituting the foam, and the polyurea produced by the condensation reaction with the isocyanate. Ru. Furthermore, when the amount of water is increased in place of inert fluorocarbon as a blowing agent, the concentration of polyurea in the resin increases, which tends to increase hardness and deteriorate physical properties.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a soft urethane foam that maintains conventional physical properties and density even when manufactured with a reduced amount of fluorocarbon.

[Means for Solving the Problems] The method for producing a highly elastic flexible urethane foam (1-(R foam) of the present invention comprises a polyol composition comprising a polyol, a blowing agent, a catalyst and other auxiliary agents, an isocyanate and In the method of manufacturing a flexible urethane foam by mixing and foaming, the bool contains 10% of a random copolymer of propylene oxide and ethylene oxide.
It is characterized by containing ~30% by weight.

For example, in the case of the cold cure type, this soft urethane foam is produced by mixing isocyanate with a polyol composition in a mixer, and then injecting the mixture into a mold at a temperature of 70°C or less and causing foaming. Ru.

A polyol composition is formed by mixing a polyol with a blowing agent, a catalyst, and other auxiliary agents.

It is preferable to use a polyfunctional polyol formed by block polymerization in which ethylene oxide is added to the terminal end of a propylene oxide polymer. Other known polyether polyols and polyester polyols that can be used in the production of urethane can also be used as appropriate depending on the physical properties of the urethane foam.

This polyol component is mixed with one polymer formed by random polymerization of propylene oxide and ethylene oxide.
When added in an amount of 0 to 30% by weight, it is possible to obtain a urethane foam that maintains its physical properties even if the amount of chlorofluorocarbon as a blowing agent is reduced.

Unlike known block-type polymers, this random polymer has a slow reactivity with isocyanates, a relatively low molecular weight, and does not increase the hardness of the formed foam or reduce its impact resilience.

Random polymer content in polyol: 10% by weight
If the content is less than 30% by weight, the addition effect will not be obtained, and if the content exceeds 30% by weight, the hardness will increase and the impact resilience will decrease, which is not preferable.

The composition ratio of propylene oxide and ethylene oxide in this random polymer is preferably 10:90 to 50:50. If the content of ethylene oxide in the random polymer is less than 50%, the effect of increasing impact resilience will be small, and this is not preferred.

Moreover, if the content of ethylene oxide exceeds 90%, the viscosity becomes high and handling becomes difficult, which is not preferable.

In addition to water, the blowing agent may be a halogen-substituted aliphatic hydrocarbon that can volatilize at low temperatures to form a foam, but like fluorocarbons, it poses environmental problems and is not preferred.

If the amount of fluorocarbon used as a blowing agent is reduced and the amount of water is increased instead, the resulting foam becomes too hard to be used as an automobile seat batt material. Therefore, adjusting the hardness by reducing the isocyanate/polyol ratio (NGO index) is not preferred because the physical properties deteriorate.

Tertiary amines are used as catalysts. For example, triethylamine, dimethylpiperazine, dimethylethanolamine, triethylenediamine, dimethylaniline, etc. can be used. Other organometallic materials can also be used.

Other auxiliary agents include silicone foam stabilizers, stabilizers, and the like.

As the isocyanate, aromatic polyisocyanates are mainly used, and diphenylmethane diisocyanate called MDI is preferably used.

When producing urethane foam, the ratio of polyol composition to isocyanate is determined based on the isocyanate index (NG
O index) is usually 80 to 150, preferably 8
It is 0-130. The hardness of the urethane foam can be adjusted using this index.

[Effect 1] In the method for producing a flexible urethane foam of the present invention, a specific amount of a random polymer of propylene oxide and ethylene oxide is contained in the polyol component.

Therefore, even if a large amount of water is used as a foaming agent, a soft urethane foam can be formed without increasing the hardness or decreasing the impact resilience. Therefore, it is possible to reduce the amount of fluorocarbon as a foaming agent.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example No. 1 is polyol A (a block polymer in which ethylene oxide is added to the end of a propylene oxide polymer) (manufactured by Sanyo Chemical Co., Ltd.: number of functional groups f = 3, molecular weight 6000, copolymer component 4% > 80 weight) Polyol B (30:70 random polymer of propylene oxide and ethylene oxide) (manufactured by Sanyo Chemical Co., Ltd.)
FA103: Number of functional groups f=3.0Hv-50>20 parts by weight, 3.5 parts of water, Freon (CFC-11>5 parts by weight, catalyst: Yoyocat-ET (manufactured by Tosoh) 0.1 parts by weight, DABCO 33L-V (manufactured by Sankyo Air Products) 0
．． 5 parts by weight of silicone foam stabilizer L-5309 (manufactured by Nippon Unica) and 1 part by weight of urethane-modified crude MDI (NCO content 22%, viscosity 600 CPS) in an amount that gives an isocyanate index of 100.
/25°C), mixed with a pressurized mixer, and poured into a mold maintained at a temperature of 45°C to foam. No. 2 (A/B-70/30) was produced in the same manner using polyol compositions with different ratios of polyol A and polyol B and the amount of DABCO 331V as a catalyst as shown in Table 1.
, No. 3 (A/B=90/10) soft urethane foam was prepared.

As a comparative example, No. 1 foil polyol ratio A/B = 60/
40) No. 2 is the case in which polyol B is not blended, the amount of water in the blowing agent is increased, the amount of fluorocarbon is reduced, and the NGO index is lowered to adjust the hardness, and No. 3 is the conventional case with a large amount of fluorocarbon. , N014 is a conventional polyol with increased water content and reduced fluorocarbon content.

The core density, 25% hardness, and impact resilience of the obtained soft urethane foams were examined.

The results are shown in Table 1.

The physical properties were measured based on the following criteria.

Core Density: A skin layer of 10 # or more was removed from the molded product, and a sample of 100 m x 100 m x 30 rrm was cut out from the remaining sample and its density was measured.

25% hardness: According to JIS K 6401.

Repulsion resilience: According to JIS K 6401.

Compared to Comparative Example No. 093, which is a conventional soft urethane foam, Examples Nos. 1 to 3 maintain the same level of physical properties in terms of density, hardness, and impact resilience. Therefore, even if the amount of water in the blowing agent is increased and the amount of fluorocarbon is decreased, a soft urethane foam similar to that obtained when conventional fluorocarbons are used can be obtained.

When the content of polyol B (random polymer) in Comparative Example No. 1 is 40%, the hardness increases and the impact resilience decreases. In Comparative Example No. 33, even if the hardness is adjusted by lowering the isocyanate index, the impact resilience decreases. Comparative example N
No. 4 is a case where the conventional composition of Comparative Example No. 2 was increased by increasing the amount of water and halving the amount of Freon, and the hardness was significantly increased and the impact resilience was also decreased.

[Effects] According to the production method of the present invention, by blending a specific amount of a random polymer of propylene oxide and ethylene oxide into the polyol component, a soft urethane foam that maintains impact resilience without increasing hardness can be easily produced. can.

Furthermore, the amount of fluorocarbon used can be reduced.

Patent applicant: Toyota Motor Corporation

Claims (1)

[Claims] (1) A method for producing flexible urethane foam by mixing and foaming a polyol composition consisting of a polyol, a blowing agent, a catalyst, and other auxiliaries with an isocyanate, in which the polyol is a mixture of propylene oxide and ethylene oxide. A method for producing a highly elastic flexible urethane foam (HR foam), comprising 10 to 30% by weight of a random copolymer.