JPH0645711B2 - Method for manufacturing flexible polyurethane foam - Google Patents

Description

Detailed Description of the Invention [Object of the Invention]

INDUSTRIAL APPLICABILITY The present invention relates to a method for producing a flexible polyurethane foam, more specifically, reacting a specific polyhydroxy compound and a polyisocyanate compound in the presence of a catalyst, a foaming agent and a specific foam stabilizer. The present invention relates to a method for producing a flexible polyurethane foam. [Prior Art] Since flexible polyurethane foam has excellent elasticity, it is widely used for cushions and backing materials for furniture, automobiles, etc., but molded foams are mostly for automobiles. The technology for producing a molded foam of soft urethane is roughly classified into a cold cure method and a hot cure method, each of which has advantages and disadvantages as described below. That is, the foam obtained by the cold cure method is commonly called HR (High Re
Silience) foam, which has excellent physical properties such as high impact resilience and SAG coefficient, and can be cured at a low temperature on the molding surface and has a short curing time, and the foam does not easily crack or shrink. Although the product has a high yield (yield), especially when the density of the foam is made low, the wet set becomes extremely bad, so that there is a drawback that it can be used only for a high-density cushion. On the other hand, in the hot cure method, the carrying temperature at the time of molding is high and the time is required to be long, and due to excess or deficiency of the amount of catalyst, temperature change of the mold, and mold shape change, cracks, shrinkage,
Although defects such as loose skin are likely to occur and the yield of products is low, the cold cure method has the advantage that low density products with excellent compression set (especially wet set) can be obtained. Therefore, in the foam obtained by this method, a low density foam is used as a backing material, and a medium to high density foam is used as a cushion. As a trend in recent years, cushions and backing materials for automobiles are not so much pursuing in-vehicle comfort and comfort as much as possible.
Product yield is decreasing, and improvement of yield has become a major issue especially for hot cure, which has a slightly poor moldability. The reason for the decrease in yield is that many insert materials are used, the product mold is becoming more and more complicated, and the mold temperature in the same mold, which is especially observed in the mold with a three-part mold, is partially It is thought that this is due to variations. In addition, most of the low-density low-hardness foams used for backing materials have been produced by blending CFCs (chlorofluorocarbons, CFCs). Therefore, CFCs are not used in accordance with the enforcement of CFCs (or The development of manufacturing methods that can significantly reduce the amount used has become an important theme. Further, in order to obtain a low-density, low-hardness foam, a long curing time is required, and there is a problem that the wet setting becomes poor. Therefore, it has such performances, that is, (1) good yield can be obtained even for complex shaped products, (2) curing time is short, and (3) foam physical properties (especially wet set) even if the density is lowered. (4) In the production of low-density foam, it is possible to eliminate or significantly eliminate the use of CFCs, and (5) increase the mold temperature at the time of raw material injection to save labor in the production process and reduce the density. (6) On the other hand, if we could develop a method for manufacturing flexible polyurethane foam, which can also be used for cushions, with high density and high hardness,
Great industrial benefits can be expected. Regarding the above-mentioned (1) to (6), several solutions have been proposed so far for each single problem (for example, regarding (1), JP-A-50-1197, 57-571
No. 5, gazette (2), JP-A-54-37198, (3)
Japanese Patent Publication No. 1-31536 for (4), Japanese Patent Laid-Open No. 57-162714 for (4), Japanese Laid-Open Patent Publication No. 1-115919, and (5) for Japanese Patent Laid-Open No. 56-67330 and 57- 195725, 59-100125, and (6) are Japanese Patent Publication No.
Japanese Patent Publication No. 48-8880) does not propose any method capable of simultaneously solving the problems (1) to (6). (Problems to be solved by the invention) The present invention solves all the above-mentioned problems (1) to (6), regardless of the product shape or use, a flexible polyurethane foam having excellent foam physical properties, which is extremely efficient. An object is to provide a method that can be manufactured well.

[Constitution of the invention]

[Means and Actions for Solving the Problems] The present invention provides a method for producing a flexible polyurethane foam by reacting a polyhydroxy compound and a polyisocyanate compound in the presence of a catalyst, a foaming agent and a cell stabilizer. The above-mentioned problems have been solved by using a polyhydroxy compound and a specific foam stabilizer. That is, in the present invention, A. As the polyhydroxy compound, a mixed polyether polyol having a hydroxyl value of 35 to 75 mgKOH / g, an ethylene oxide content of 25 to 60% by weight, and a primary primary OH group of 40 mol% or more in all OH groups or a modified product thereof is used. Compound represented by the following formula as a bubble stabilizer 0.3 per 100 parts by weight of the above mixed polyether polyol.
It is characterized in that it is used in a proportion of at least parts by weight. The polyhydroxy compound used in the present invention comprises a mixed polyether polyol containing two or more kinds of polyether polyols or a modified product thereof. That is, as the mixed polyether polyol of the present invention or a modified product thereof, a starting material having two or more active hydrogens, in the presence of a basic catalyst,
A compound obtained by mixing two or more kinds of individual polyether polyols obtained by addition-polymerizing alkylene oxide in a random or block form, or an addition polymerization of alkylene oxide in a mixture of two or more kinds of individual starting materials by the same method as described above. Examples thereof include compounds obtained by the above, or modified products obtained by graft-polymerizing ethylenically unsaturated monomers with these (hereinafter, also referred to as polymer polyols). Examples of the starting material include propylene glycol, ethylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, sorbitol, sugars and other polyhydric alcohols, monoethanolamine, Diethanolamine, triethanolamine, ethylenediamine,
Any of amines such as triethylenediamine can be used. Particularly preferred starting materials are compounds having three active hydrogens such as glycerin and trimethylolpropane. Next, as the alkylene oxide, ethylene oxide, propylene oxide, butylene oxide, styrene oxide or the like can be used,
The most preferable examples are ethylene oxide (hereinafter abbreviated as EO) and propylene oxide (hereinafter abbreviated as PO). As the modified product, a polyether polyol obtained from the starting material and the alkylene oxide is grafted with an ethylenically unsaturated monomer such as acrylonitrile (hereinafter abbreviated as AN) or styrene (hereinafter abbreviated as ST) as appropriate. A polymerized product can be used. Then, these mixed polyether polyols or modified products thereof are required to satisfy the following requirements. That is, the hydroxyl value is 35 to 75 mg KO / g, the weight ratio of EO to other alkylene oxide is 25 to 60:75 to 40, and all OH groups are
It is necessary to prepare such that 40 mol% or more, preferably 50 to 85 mol%, is a terminal primary OH group. When the hydroxyl value is lower than 35 mgKOH / g, the foam has a good appearance, but the compression set is poor, and a foam suitable as a cushioning material cannot be obtained. On the other hand, when the hydroxyl value is higher than 75 mgKOH / g, cell openability, impact resilience and compression set are poor, and good foam cannot be obtained. Further, when the ethylene oxide content is less than 25% by weight, the resulting foam becomes a closed cell and the compression set and impact resilience are poor, and when the ethylene oxide content is more than 60% by weight, the cells of the foam become It becomes coarse and sometimes collapses. Furthermore, when the terminal primary OH group is less than 40 mol%, the skin of the foam is weak and the curing time becomes long,
It becomes of little practicality. Next, in the present invention, a specific compound represented by the following general formula is used as a bubble stabilizer. {[R ₂ SiO] a [Q]} b In the above general formula, it is preferable that [R ₂ SiO] a has a molecular weight of 500 to 10000 and a content of 20 to 50% by weight, and Q has a molecular weight. The content is preferably 300 to 10,000, and the content is preferably 80 to 50% by weight. The above R is a monovalent hydrocarbon having no aliphatic unsaturated bond and having 1 to 20 carbon atoms, particularly CH.
_It is preferably a lower alkyl group such as ₃ or a phenyl group. Q is an oxyalkylene group consisting of (C ₂ H ₄ O) y ¹ , (C ₃ H ₆ O) y ² or a combination thereof, and in particular, (Y ¹ , y ² ; 1 or more, y ¹ + y ² = 4 or more) is preferable. The molecular weight of the foam stabilizer is preferably 65,000 or more, and the upper limit is not particularly limited. However,
If the molecular weight is too high, the viscosity will be increased, so that the desired physical properties of the foam will be obtained, but it will be impractical in terms of workability. When R, a, y ¹ , y ² and b in the general formula are out of the specified range, the foam surface may be roughened, cracked, collapsed or shrunk, or a normal foam cannot be obtained. Even if a good foam is obtained, only a foam lacking in practical use can be obtained because the impact resilience and the compression set are deteriorated. Next, the blending amount of the foam stabilizer is 0.3 parts by weight or more per 100 parts by weight of the mixed polyether polyol, and is 0.5 to
It is preferably 3 parts by weight. If it is less than 0.3 parts by weight, the cells of the foam become coarse, and cracks and collapses occur. The bubble stabilizer represented by the above general formula used in the present invention may be optionally used in combination with a bubble stabilizer generally used in the art. Examples of the bubble stabilizer used in combination include compounds represented by the following general formula. Examples of the polyisocyanate compound used in the present invention include tolylene diisocyanate, phenylene diisocyanate, and diphenylmethane diisocyanate.
As the catalyst, triethylenediamine and its formate, dimethylethanolamine, tetramethylhexamethylenediamine, N-methylmorpholine, amine catalysts such as N-ethylmorpholine, stannous octoate, tin catalyst such as dibutyltin dilaurate, etc. Is mentioned. Further, water is usually used as the foaming agent, but in some cases, trichlorofluoromethane, dichlorofluoromethane, a low boiling point solvent such as methylene chloride can be added,
In addition, additives such as pigments, flame retardants, antistatic agents, and cross-linking agents can be added if necessary, and raw materials and molding methods other than the polyether polyol and the foam stabilizer are not particularly limited. Any conventionally known method can be applied to the method for producing the flexible polyurethane foam. In this way, the polyurethane foam obtained by the present invention has extremely good compression set (especially wet set), so that the density can be further lowered and the hardness can be lowered as compared with the conventional hot cure method. Therefore, it is possible to produce a practical low-hardness foam without using CFC at all, or even if the use thereof is largely eliminated. On the contrary, by using the above-mentioned polymer polyol as a blending component, it is possible to increase hardness, and a wide range of physical properties can be obtained by changing the blending composition and blending ratio. Further, since the present invention has an extremely wide catalyst range and a mold temperature range at the time of injecting raw materials as compared with the conventional method, strict control of the catalyst amount and the mold temperature as in the conventional method is not required, and the workability is excellent. Not only that, but because the curing time is fast, productivity is greatly improved. [Examples] Examples and effects of embodying the invention will be described below with reference to examples and comparative examples, but the exemplification is merely for the purpose of explanation and is not intended to limit the idea of the invention. Further, the value shown as part or% below means part by weight or% by weight unless otherwise specified. Examples 1-10 and Comparative Examples 1-11 The various polyether polyols, polymer polyols and foam stabilizers used in the Examples and Comparative Examples (see Tables 1, 2 and 3) were prepared by known methods. Next, 100 parts of various polyether polyols, 1.2 parts of bubble stabilizer, 5.0 parts of water, TEDA-L33 (manufactured by Tosoh, 33% dipropylene glycol solution of triethylenediamine) 0.3
Parts, stanna octoate 0.13 parts in a container,
The temperature in the container was adjusted to 22 ° C. Then, premix with a turbine stirrer at 3500 rpm for 40 seconds, then use TDI-80 at 22 ℃.
(Mitsubishi Kasei Tolylene Diisocyanate) was added in a stoichiometric amount (NCOindex 100), stirred for 5 seconds, and preliminarily adjusted to 40 ° C with 400 (W) × 400 (L) × 100 (H) mm aluminum metal It was poured into a mold and made into a foam. About 100 seconds after adding TDI-80, the filling into the mold was completed. Then, the mold was placed in a hot air oven at 170 ° C. for 8 minutes for curing to obtain a flexible polyurethane mold foam. The foam physical properties of this foam were measured according to JIS K-6401, and the state of the foam was examined. The results are shown in Tables -4 and 5. Examples 11 to 18-Catalyst amount test-Formation was performed in the same manner as in Example 2 except for the catalyst amount,
The results of the relationship among the amount of catalyst, the physical properties of the foam, and the foam state are shown in Table-6. Comparative Examples 12 to 17-Catalyst Amount Test-Formation was performed in the same manner as in Comparative Example 1 except for the amount of catalyst, and the relationship between the amount of catalyst and the physical properties and state of the foam was determined. Examples 19 to 23 Comparative Examples 18 to 21-Test of Mold Temperature Range-Under the same conditions as in Example 2 and Comparative Example 1, only the mold temperature at the time of raw material injection was changed to form a foam. The obtained foam was further cut off in appearance and examined only in the state of the core. The results are shown in Table-8. Examples 24 to 25, Comparative Example 22-Cureability Test-Under the same conditions as in Examples 2 and 17, and Comparative Example 3, only the curing time was changed to form a foam. Only the foam state when demolded from the mold was investigated and shown in Table-9. Examples 26 to 29 Comparative Example 23-Mixing Test of Bubble Stabilizer-Formation was performed in the same manner as in Example 1 except for the type and amount of the bubble stabilizer, and the physical properties and state of the foam were examined. It was shown to. Example 30 and Comparative Example 24-Moldability Test-Using a foaming machine, a moldability test was performed by replacing the foaming mold with a complicated mold type in which the best foam is difficult to obtain.
The defective rate of the obtained foam was investigated, and the results are shown in Table-11. As described above, the following can be understood from the results of Tables 4 to 11. (1) Foam Properties Examples 1 to 10 and Comparative Examples 1 to 11 (Tables 4 and 5) Among the examples according to the present invention, when the polymer polyol is not blended, the hardness is 4 to 5 kg lower and the compression set is lower. It is possible to obtain a product excellent in (especially wet set), non-CFC use or the use of CFC can be significantly reduced, and further reduction in density can be achieved. The wet set value in the low density formulation example corresponds to a core density value of 35 Kg / m ³ according to the prior art. Further, when a polymer polyol is blended, a high-level foam can also be obtained. (2) Control Range of Catalyst Amount Examples 11 to 18 and Comparative Examples 12 to 17 (Tables 6 and 7) It is understood that the method of the present invention is wider than the conventional method incomparably. (3) Mold temperature control range Examples 19 to 23, Comparative Examples 18 to 21 (Table 8) The conventional method is limited to around 40 ° C, whereas the method of the present invention has a wide range of 30 to 60 ° C. Good results have been obtained in a wide temperature range. (4) Curability Examples 24 to 25, Comparative Example 22 (Table 9) In the examples of the present invention, the mold can be removed in about 1/2 time as compared with the conventional method, and the process speed can be increased. (5) Moldability (Yield) Example 30, Comparative Example 24 (Table 11) In the conventional method, about half of the foams had some defects, whereas in the method of the present invention, the defective rate was only 2%. The results were as follows and were extremely excellent.

【The invention's effect】

In the method of the present invention, it is possible to manufacture a low-density flexible polyurethane foam having a good compression set, by breaking the common knowledge in the industry that the compression set (particularly wet set) is deteriorated when the foam density is lowered. In addition, those with good curing properties have higher hardness, narrower catalyst width and mold temperature width,
In addition, the common sense such as a decrease in product yield is overcome, and a foam having very good physical properties can be stably produced in a short time. Furthermore, since soft foam can be obtained without using CFC, it can contribute to boundary preservation. On the other hand, when a polymer polyol is used as the polyhydroxy compound, hardness can be increased and a wide range of physical properties can be obtained depending on the compounding composition, and a wide range of applications can be achieved.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 75:04

Claims (1)

[Claims] 1. A method for producing a flexible polyurethane foam by reacting a polyhydroxy compound and a polyisocyanate compound in the presence of a catalyst, a foaming agent and a cell stabilizer. As the polyhydroxy compound, a mixed polyether polyol having a hydroxyl value of 35 to 75 mgKOH / g, an ethylene oxide content of 25 to 60% by weight, and a primary primary OH group of 40 mol% or more in all OH groups or a modified product thereof is used. Compound represented by the following formula as a bubble stabilizer 0.3 per 100 parts by weight of the above mixed polyether polyol.
A method for producing a flexible polyurethane foam, characterized in that it is used in a proportion of at least parts by weight.