JPH02272012A - Production of soft polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain the subject foam contributing to environmental maintenance without using fluorine-based foaming agent by mixing specific polyhydroxy compound, water as foaming agent, air bubble stabilizer, foaming catalyst, other additives and polyisocyanate and reacting. CONSTITUTION:Ethylene oxide and propylene oxide are subjected to addition polymerization in block-like or randomly to obtain (A) a polyether polyol containing 5-30wt.% ethylene oxide and terminal hydroxyl group having <=20wt.% primary hydroxyl group and having >=2.8 average number of functional groups and 1000-1500 molecular weight per one hydroxyl group. Then, the polymer A is mixed with (B) a polyhydroxy compound composed of polyether polyol containing terminal hydroxyl group having <=10wt.% primary hydroxyl group and having 2-3 average number of functional groups and 100-600 molecular weight per one hydroxyl group, (C) polyisocyanate and (D) foaming agent, air bubble stabilizer, foaming catalyst and other additives, and reacted to afford the aimed urethane foam.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing two polyurethane foams, in particular a method for producing flexible polyurethane mold foams with low hardness.

(Prior art) Generally, polyurethane molded foam is manufactured by blending a polyhydroxy compound, polyisocyanate, a foam stabilizer, a foaming catalyst, a foaming agent, etc., injecting the mixture into a mold, and heating and reacting the mixture. Because it is light and has excellent elasticity, it is widely used as cushioning material for furniture and automobiles.

Seat cushions of this molded product are generally divided into two types: seat cushions and back cushions, and foams with different hardnesses are usually selected depending on the purpose.

That is, the high-hardness foam is used as a backrest, and the low-hardness, ie, soft, foam is used as a backrest.

By the way, in the production of the above-mentioned low hardness foam, the most effective method is to use a fluorine-based low boiling point blowing agent such as Freon 11, and if necessary, technology for foaming with a lower NC010H index or bifunctional foam can also be used. Techniques that use glossy polyols as part of polyhydroxy compounds are used in combination.

(Problem to be Solved by the Invention) However, in the production of low hardness flexible polyurethane foam using conventional fluorine-based blowing agents such as Freon 11, the ozone layer in the upper layer of the atmosphere is destroyed by the released Freon gas. It becomes a problem. For this reason, currently UME
P (United Nations Environment Programme) and other organizations are considering measures to restrict the use of chlorofluorocarbons, and they are scheduled to be implemented from July of this year in accordance with the Montreal Protocol of the Ozone Protective Layer Protection Convention.

In addition, the technology of foaming with a low NGO10H index and the technology of using bifunctional polyol as part of the polyhydroxyl compound have only a small effect on hardness reduction, and if you want to increase the hardness reduction rate, you need to increase the amount of foam. Conventional low-hardness polyurethane resin that uses freon gas as a blowing agent has problems such as an increase in hardness, a decrease in curing speed, and a worsening of compression set.
/ It is not an alternative technology to the tanform manufacturing method.

Therefore, it is important to quickly establish a method for manufacturing low-hardness, flexible polyurethane foam that does not use fluorocarbon gas.

It is important from a global perspective.

In addition, when fluorocarbon gas is used as a foaming agent.

Generally speaking, the fuel cost required for curing tends to be higher than when this gas is not used.

In view of the above circumstances, an object of the present invention is to develop a method for producing a flexible polyurethane foam with low hardness without using any fluorocarbon gas.

(Means for solving the problem) [Summary] Hardness 13 kg according to JIS -6401 related to Kibatsu 11
The following method for producing flexible polyurethane foam is used to produce flexible polyurethane foam from a polyhydroxy compound, a polyisocyanate, a blowing agent, a foam stabilizer, a foaming catalyst, and other additives. is 2.8 or more, ethylene oxide and propylene oxide are added in a block or random manner, and the molecular weight per hydroxide is 1000 to 150.
A polyether polyol (hereinafter referred to as polyether polyol A) with an ethylene oxide content of 5 to 30i11% and 2 and 20% or less of primary hydroxyl groups among terminal hydroxyl groups, and an average number of ethylene oxide groups of 2 to 30i11% (hereinafter referred to as polyether polyol A). 3, water r! A polyether polyol (hereinafter referred to as polyether polyol B) with a molecular weight of 100 to 600 per 1° I# group and 10% or less of primary hydroxyl groups among the terminal hydroxyl groups is used as a polyether polyol-containing/polyether polyol. Polyol B (
ffli ratio) = 95-70 mixed at a ratio of 15-30,
The gist is that the mixture is a polyether polyol having an average number of functional groups of 2.5 to 3, one blowing agent is water, and no fluorocarbon gas is used.

The various conditions constituting the five shots IjI will be explained below.

[Polyhydroxy Compound] The polyhydroxy compound used in the present invention consists of two types of polyether polyols.

The first polyether polyol A is ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol,
Ethylene oxide and propylene oxide are added in a block or random manner using an initiator containing one or a mixture of two or more polyfunctional polyols such as sucrose so that the average number of radicals is 2.8 or more. The molecular weight per hydroxyl group is 1000-1500, the content of ethylene oxide is 5-30i%, and the r:51 class hydroxyl group accounts for 20% or less of the terminal hydroxyl groups. .

In addition, polyether polyol A can be substituted by mixing individually synthesized polyether polyols as long as the structure and composition of the mixture is within the above-mentioned range. You may substitute alkylene oxide other than ethylene oxide, such as butylene oxide.

The second polyether polyol glycol, propylene glycol, glycerin, polyfunctional polyols such as trimethylolpropane, pentaerythritol, nrubitol, sucrose, etc., and amine compounds such as ammonia, triethanolamine, ethylenediamine, aniline, etc. with an average functional group number of 2 to 3. Using as an initiator one or a mixture of two or more of these, propylene oxide or It has added fullylene oxide such as ethylene oxide.

As mentioned above, even if polyether polyol B is mixed with individually synthesized polyether polyols, the structure of the mixture will not change! Substitutions are possible as long as the configuration is within the above range.

The polyhydroxy compound of the present invention contains the polyether polyols A and B of the above-mentioned zIi types in a polyether polyol/polyether polyol B (weight ratio); 95 to 7
A mixture having a ratio of 015 to 30 and an average number of functional groups of 2.5 to 3 is used.

Using polyether polyols outside the aforementioned ranges will result in
None of these methods are suitable for the production of low-hardness, flexible molded polyurethane foam, which is the purpose of this invention. For example, among the terminal hydroxyl groups of polyether polyol A, 2 primary hydroxyl groups
If it exceeds 0%, the hardness will increase and the low hardness flexible molded polyurethane foam that is the objective of the IjI of the present invention cannot be obtained.

Similarly, among the terminal hydroxyl groups of polyether polyol B,
If the primary hydroxyl group content exceeds 10%, the hardness increases) JO, a low hardness, flexible molded polyurethane foam cannot be obtained.

Moreover, if the content of ethylene oxide in polyether polyol A is less than 5%, the time required for curing increases, making it unsuitable as an alternative to the conventional technique using fluorocarbon gas.

Even if polyether polyol A is used alone without using polyether polyol B, the time required for curing increases, so it is not suitable as an alternative to the conventional technology.
When used alone, the properties of flexible polyurethane foam, such as elasticity, cannot be obtained.

[Blowing Catalyst] The blowing catalyst used in the present invention is one that is widely used in flexible polyurethane foams. That is, amine compounds such as triethylenediamine, tetramethylhexamethylenediamine, and toethylmorpholine, and organometallic compounds such as stannath dioctoate and dibutyltin dilaurate are used.

[Blowing agent] The blowing agent used in step 1 is water. The amount used is in the range of 2 to 7 parts per 100 parts of the polyhydroxy compound.

[Polyisocyanate] The polyinsyanate used in unexploited [51] is 2.

4-Tolylene diincyanate (2.4-TD I )
, 2.

S-tolylene diisocyanate (2.6-TD I )
, polymethylene polyphenylene polyisocyanate (
Crude MDI), carpodimide-modified diphenylmethane diincyanate (liquid MDI), and prepolymer compounds having terminal isocyanate groups obtained by reacting a part of the isocyanate component with hydroxyl groups, etc., which may be used alone or in combination. used.

Foam Stabilizer, etc.] The foam stabilizer used in Unexploded 151 is a silicon-based foam stabilizer such as a known siloxane/oxyalkylene copolymer.

The foam obtained by the present invention contains colorants, flame retardants,
Various additives such as stabilizers can be added.

[Molding method 1 Molding according to the method of the present invention is performed according to a known method. Let me give you a laboratory example.

The polyisocyanate compound is added to the mixture of each raw material other than the polyisocyanate compound in a paper pot, quickly mixed for 5 to 10 seconds, and then poured into a mold of the desired shape and heated to harden to obtain a foam. I can do it. Further, industrially, it is preferable to use a low pressure type or high pressure type mixing discharge machine of 2r&min or more as a mixing means.

Note that the method of the present invention can also be carried out in combination with a conventional method for manufacturing low-hardness foam using fluorocarbon gas.

(Function) The polyurethane molded foam obtained by the present invention is J
When the hardness was measured according to the IS K-6401 method, the hardness was low at 13 to 8 or less, and the appearance and appearance of the foam were low.
The cell condition is also good. Moreover, compared to the case of using fluorocarbon gas, it is possible to lower the curing temperature and shorten the curing time during production, so it is of great value industrially.

(Example) The present invention will be described in more detail with reference to Reference Examples, Examples, and Comparative Examples below, but the present invention is not limited thereto.

Reference example.

Production of polyether polyols (1) to (8): Table 1 shows the polyether polyols used in Examples and Comparative Examples.
Using the compound shown in as raw material.

It was manufactured according to known polyether polyol manufacturing techniques.

Example-1 225all of polyether polyol (1), 75811 of polyether polyol (4), 13.5 parts of water2
Silicone foam stabilizer L-5740M (Nippon Unicar@
I) 3.8m, Stanus dioctoate 0.45 parts,
Add 0.9 parts of triethylenediamine, 3 fJ, and N-ethylmorpholine to two paper cups.
After stirring for 0 seconds, TDI-80 (8:2 mixture of 2,4-tolylene diisocyanate and 2,6-)lylene diisocyanate, manufactured by MD) was added to NGOlo! After adding so that the index is 100 and stirring for 5 seconds, mix it with a vertical 350 mm x 1350 mm set at 40°C.
・It was poured into an aluminum mold with a height of 100 mm and formed into a form. This mold was then heated and cured in an oven set at 160° C. for 8 minutes.

As shown in Table 2, the hardness of the obtained foam was significantly lower than that of Comparative Example 1, which corresponds to conventional water-foamed flexible molded polyurethane foam, and other foam properties were also good. It was at the same level as Comparative Example 2 using chlorofluorocarbon gas.

Example-2 225 parts of the polyether polyol (1) of Example-1 was added to 225 parts of the polyether polyol (2), and 225 parts of the polyether polyol (075 parts) was added to the polyether polyol (s
) All molding was performed in the same manner as in Example-1 except that the content was changed to 7sB%. As shown in Table 2, the obtained foam had low hardness as in Example 1.

Comparative Example-1 All procedures were carried out in the same manner as in Example-1, except that 225 parts of polyether polyol (1) and 75 parts of polyether polyol (4) in Example-5 were changed to 300 parts of polyether polyol (3). It was rIt type. The results are shown in Table-2.

Comparative Example-2 The blowing agent of Comparative Example-1 was added to 11 parts of Freon in addition to 13.5 parts of water.
All molding was performed in the same manner as in Comparative Example-1 except that 18 parts of was used. The results are shown in Table-2.

Comparative Example-3 All the same as Example-1 except that 225 parts of polyether polyol ([) and 300 parts of polyether polyol (2) of Example-1 were replaced with 300 parts of polyether polyol (2).
When the same method as above was used, the foam adhered to the mold and could not be removed due to insufficient curing.

Comparative Example-4 All except that 225 parts of polyether polyol (1) in Example-1 was changed to 225 parts of polyether polyol (2), and 7561 parts of polyether polyol (4) was changed to 75 parts of polyether polyol (B). It was molded in the same manner as in Example-1. The results are shown in Table-2.

(Effects of the Invention) As explained above, the present invention provides a method for producing flexible polyurethane foam of excellent quality without using a fluorine-based blowing agent, thereby contributing not only to the a industry but also to environmental protection. Can contribute.

Claims (1)

[Claims] (1) When producing flexible polyurethane foam from a polyhydroxy compound, polyisocyanate, blowing agent, foam stabilizer, blowing catalyst, and other additives, the polyhydroxy compound has an average functional group number of 2.8 or more, and ethylene Oxide and propylene oxide are added in a block or random manner, the molecular weight per hydroxyl group is 1000 to 1500, the ethylene oxide content is 5 to 30% by weight, and the primary hydroxyl group is 20% of the terminal hydroxyl groups. The following polyether polyol (hereinafter referred to as polyether polyol A) and the average number of functional groups from 2 to
In step 3, a polyether polyol (hereinafter referred to as polyether polyol B) with a molecular weight per hydroxyl group of 100 to 600 and 10% or less of primary hydroxyl groups among terminal hydroxyl groups is converted into polyether polyol A/polyether Polyol B (weight ratio) is a polyether polyol mixed at a ratio of 95 to 70/5 to 30, and the average number of functional groups in the mixture is 2.5 to 3, characterized in that the blowing agent is water. JISK-640
A method for producing a flexible polyurethane molded foam having a hardness of 13 kg or less according to No. 1, especially without using fluorocarbon gas.