JPH0418435A - Production of flexible polyurethane foam - Google Patents

Abstract

PURPOSE:To efficiently produce a flexible polyurethane foam having excellent physical properties of foam by reacting a specific polyhydroxy compound with a polyisocyanate compound in the presence of a specific foam stabilizer, etc. CONSTITUTION:(A) A polyhydroxy compound being a mixed polyether polyol (modified material) having 35-75mg KOH/g hydroxyl value, 25-60wt.% ethylene oxide content and >=40mol% terminal primary OH group in total OH group is reacted with (B) a polyisocyanate compound in the presence of (C) a catalyst, (D) foaming agent and (E) foam stabilizer expressed by formula I [R is monovalent hydrocarbon not containing aliphatic unsaturated hydrocarbon; Y is divalent organic group; a is >=60; Q is formula II and/or formula III (y1 and y2 are >=4 and >=1 in the case of combination and sum thereof is >=4; b is >=4).

Description

[Detailed description of the invention] [Purpose of the invention]

[Industrial Application Field] The present invention relates to a method for producing flexible polyurethane foam, and more specifically, a method for producing a flexible polyurethane foam, and more specifically, a method for reacting a specific polyhydroxy compound and a polyisocyanate compound in the presence of a catalyst, a blowing agent, and a specific foam stabilizer. The present invention relates to a method for producing flexible polyurethane foam. [Prior Art] Flexible polyurethane foam has excellent elasticity and is therefore widely used in cushions and backrest materials for furniture, automobiles, etc., but molded foam is mostly used for automobiles. Techniques for producing soft urethane mold forms are broadly classified into cold curing methods and hot curing methods, each of which has advantages and disadvantages as described below. That is, the foam obtained by the cold cure method is commonly called) (R (Hi
gh Re5ilience) 7 *-mu,
It has excellent physical properties such as high impact resilience and SAG coefficient, and can be cured at low temperatures on the molding surface, with a short curing time, and the foam is resistant to cracks and shrinkage, resulting in improved product yield. ), but on the other hand, when the density of the foam is reduced, wet safety
/ ) becomes extremely poor, so it has the disadvantage that it can only be used for high-density cushions. On the other hand, in the hot curing method, the curing temperature during molding is high and the curing time is long, and cracks, shrinkage,
Although it has drawbacks such as loose skin defects and low product yield, it has the advantage of producing low-density products with better compression set (particularly wet set) than the cold cure method. Therefore, the low density foam obtained by this method is used for backrest materials, and the medium to high density foams are used for cushions. In recent years, the product yield of cushions and backrest materials for automobiles has been decreasing due to the pursuit of maximum interior comfort and interior comfort. Improvement has become a serious issue. The reason for the decrease in yield is that a large number of various insert materials are used, the shape of the product is becoming more and more complex, and the mold temperature within the same mold is partially reduced, especially in the case of three-part molds. This is thought to be due to the paralysis. In addition, the low-density, low-hardness foams used for backrest materials have mostly been produced with fluorocarbons (chlorofluorocarbons, CFCs) in them. The development of manufacturing methods that do not require (or can significantly reduce the amount used) is becoming an important theme. In addition, in order to obtain a low-density, low-hardness foam, a long curing time is required, and there is also the problem of poor wet setting. Therefore, we have developed a system that combines the following properties: (1) Good yields can be obtained even for products with complex shapes, (2) Short curing time, and (3) Form physical properties (especially wet set) even when the density is reduced. ) is good, (4) CFCs are not used or their use can be significantly reduced in the production of low-density foam, and (5) the mold temperature during raw material injection is raised, resulting in labor-saving and low-density production processes. (6) On the other hand, if we could develop a method for manufacturing flexible polyurethane foam that can be used for cushions with high heat and hardness,
We can expect a great deal of industrial success. Regarding (1) to (6) above, several solutions have been proposed so far for each individual problem (for example, (]) is disclosed in Japanese Patent Laid-Open No. 501197, Japanese Patent Application Laid-open No. 57 -5715 Publication, (2) is published in JP-A-54-37198, (3) is published in Time-Bun 1-31536, and (4) is published in JP-A-57-1989.
Publication No. 162714, Japanese Patent Publication No. 162714! -115919 publication,
Regarding (5), Japanese Patent Application Laid-Open No. 58-87330, Japanese Patent Publication No. 57-195725, and Japanese Patent Application No. 59-10012
Regarding (6), Japanese Patent Publication No. 4G-24255, Publication No. 48-8880, etc.), (1) to (
No method has been proposed that can solve all of the problems in 6) at the same time. [Problems to be Solved by the Invention] The present invention solves all of the problems (1) to (6) as described above, and produces flexible polyurethane foam with excellent foam properties in an extremely efficient manner regardless of the product shape or use. The objective is to provide a method that can be manufactured easily.

[Structure of the invention]

[Means and effects for solving the problems] The present invention provides a method for producing flexible polyurethane foam by reacting a polyhydroxy compound and a polyincyanate compound in the presence of a catalyst, a blowing agent, and a foam stabilizer. The above problem was solved by using a polyhydroquine compound and a specific foam stabilizer. That is, in the present invention, A polyhydroxy compound has a hydroxyl value of 35 to 75 mgKOH/g
A mixed polyether polyol or a modified product thereof having an ethylene oxide content of 25 to 80% by weight and a terminal primary OH group of 40 mol% or more in all OH groups is used as B, and a compound f[ Y(
R2SiO) aR2siYO] [Q] ) b
100 parts by weight of the above mixed polyether polyol
．． It is characterized in that it is used in a proportion of 3 parts by weight or more. The polyhydroxy compound used in the present invention consists of a mixed polyether polyol containing two or more types of polyether polyols or a modified product thereof. That is, the mixed polyether polyol of the present invention or its modified product is an individual polyether polyol obtained by random or block addition polymerization of an alkylene oxide to a starting material having two or more active hydrogens in the presence of a basic catalyst. A compound obtained by addition-polymerizing a mixture of two or more types of starting materials with fullylene oxide in the same manner as above, or an ethylenically unsaturated compound of these. Modified products obtained by kraft polymerization of Shitsummer (hereinafter also referred to as polymer polyols) can be mentioned. Examples of the starting materials include polyhydric alcohols such as propylene glycol, ethylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, sorbitol, sugar, monoethanolamine, Any of amines such as jetanolamine, triethanolamine, ethylenediamine, and triethylenediamine can be used. Particularly preferred starting materials are compounds having three active hydrogen atoms, such as glycerin and trimethylolpropane. Next, as the alkylene oxide, any of ethylene oxide, propylene oxide, petite oxide, styrene oxide, etc. can be used, but the most preferable examples are ethylene oxide (hereinafter abbreviated as 1E○) and propylene oxide (abbreviated as PO). ). In addition, as the modified product, - is grafted onto the polyether polyol obtained as described above in 5 or more with an ethylenically unsaturated 7-merase such as acrylonitrile (hereinafter abbreviated as AN) or styrene (hereinafter abbreviated as ST). Polymerized products can be used. These mixed polyether polyols or modified products thereof need to be prepared so as to satisfy the following requirements. In other words, the hydroxyl value is 35-75mgKOH
/g, preferably 45-60mgKOH/g,
The weight ratio of E○ and other alkylene oxides is 25 to 8
0:75 to 40, and 40 of the total OH groups
mol% or more, preferably 50 to 80 mol%, of terminal primary O
It is prepared to be an H group. Regarding the hydroxyl value, if it is lower than 35 mgKOH/g, the appearance of the foam will be good, but the compression set will be poor.
A foam suitable for cushioning material cannot be obtained. On the other hand, what about the hydroxyl value? When it is higher than 5 mgKOH/g, cell openness, impact resilience, and compression set are poor, and a good form cannot be obtained either. Furthermore, when the ethylene oxide content is less than 25% by weight, the resulting foam becomes oily foam, has poor compression set and impact resilience, and has an ethylene oxide content of 6% by weight.
If it is more than 0% by weight, the cells of the foam become coarse and sometimes collapse. Furthermore, if the content of one terminal primary 0) group is less than 40 mol %, the skin of the foam will be weak and the curing time will be long, resulting in poor practicality. Next, in the present invention, as described above, a compound represented by the following general formula is used as a bubble stabilizer, but ([Y(RzS
iO) aTosiYO] [Ql l b In the general formula, (RzSiO)aRzSi has a molecular weight of 500 to 1
0,000 and the content is preferably 20 to 50% by weight, and it is also preferable that Q has a molecular weight of 300 to 10,000 and the content is 80 to 50% by weight. Y is -CH2CH2-, -CH2CH2CH2-, -C
H2CH2CHzCH2--((1:HzbCo- or -(CH2)3NHCO- is preferred, and
The above R is preferably a monovalent hydrocarbon containing no aliphatic unsaturated bond and having 1 to 20 carbon atoms, particularly a lower alkyl group such as CH3 or a phenyl group. Also, as mentioned above, Q is (C2H40)y', (C3H6
0) An oxyalkylene group consisting of y or a combination thereof, especially (CzHaOi to iC:5H60)y
2 (y', !2; 1 or more and yl -1-72 = 4 or more). The molecular weight of the bubble stabilizer is preferably 30,000 or more, and the upper limit is not particularly limited.However, if the molecular weight is too high, the viscosity will increase, so although the desired foam properties can be obtained, it may be difficult to This makes it impractical in terms of practicality. In addition, in the general formula (7) R, a, yl, y2. If b and Y are outside the specified ranges, the foam surface may become rough, cracked, collapse, shrink, etc., or a normal foam may not be obtained, or even if a good foam is obtained, the impact resilience may deteriorate. If the compression set is poor, you will only get a form that is not practical. Next, the amount of the foam stabilizer is 0.3 parts by weight or more per 100 parts of the mixed polyether polyol, and 0.
．． The amount is preferably 5 to 3 parts by weight, and if it is less than 0.3 parts by weight, the cells of the foam become rough, cracks, collapse, etc. occur. In the method of the present invention, the foam stabilizer represented by the above general formula may be used in combination with a foam stabilizer commonly used in the art, if necessary. Examples of the bubble stabilizer used in combination include compounds represented by the following general formula. R35iO(RzSiO) a (R5iO) b
5iR3YO (C2HaO)! '(C3H60)y2
R Polyincyanate compounds used in the present invention include tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, etc.
Catalysts include triethylene diamine and its formate salts, amine catalysts such as dimethylethanolamine, tetramethylhexamethylene diamine, tomethylmorpholine, and N-ethylmorpholine, and tin catalysts such as stannath octoate and diptylthine dilaurate. can be mentioned. Also 1
Water is usually used as the blowing agent, but in some cases it is also possible to mix in low boiling point solvents such as trichlorofluoromethane, dichlorofluoromethane, methylene chloride, etc. In addition, pigments, flame retardants, antistatic agents, crosslinkers, etc. can be added as necessary. For raw materials and molding methods other than polyether polyol and foam stabilizer,
It is not particularly limited. As a method for producing flexible polyurethane foam, any conventionally known method can be applied. In this way, the polyurethane foam obtained by the present invention has extremely good compression set (especially wet set), so it can be lowered in density and hardness than the conventional hot curing method. Therefore, it is possible to produce a practical low-hardness foam without using fluorocarbons at all or with a significant reduction in the use of fluorocarbons. On the other hand, by using the above-mentioned polymer polyol as a compounding component, it is possible to increase the hardness, and a wide range of physical properties can be obtained by changing the compounding composition and compounding ratio. Furthermore, since the catalyst range and mold temperature range during raw material injection are extremely wide in the present invention compared to conventional methods, there is no need to strictly control the amount of catalyst and mold temperature as in conventional methods, and the process is superior in workability. Instead, curing time is fast, which greatly improves productivity. [Example] Examples and effects of embodying the invention will be described below using Examples and Comparative Examples, but the examples are merely for explanation and are not intended to limit the idea of the invention. Moreover, the values shown below as parts or % indicate parts by weight or % by weight unless otherwise specified. Examples 1 to 10 and Comparative Examples 1 to 11 Various polyether polyols, polymer polyols, and foam stabilizers (see Tables 1.2 and 3) used in the Examples and Comparative Examples were prepared by known methods. Next, 100 parts of various polyether polyols, 1.2 parts of bubble stabilizer, 5.0 parts of water, 0.3 parts of TEDA-L33 (manufactured by Tosoh, 33% dipropylene glycol solution of triethylene diamine), and Stanus octoate. 0.13
The temperature inside the container was adjusted to 22°C, and the mixture was stirred at 3500 rpm using a turbine type stirrer.
After pre-mixing for seconds, add TDI-80 (tolylene diisocyanate manufactured by Mitsubishi Kasei) at 22°C to a stoichiometric amount (NCOi
ndex 100), stir for 5 seconds, and preheat to 40°C.
400 (W) x 400 (L) x 110 with temperature controlled
0(H)Il was injected into an aluminum mold to form a foam. Approximately 100 seconds after the addition of TDI-80, the mold was placed in a hot air oven at 170° C. for 8 minutes for curing to obtain a flexible polyurethane mold form. The physical properties of this foam were measured according to JIS K-8401 to examine the state of the foam. The results are shown in Tables 4 and 5. Examples 11 to 18 - Test of catalyst amount - Foaming was carried out in the same manner as in Example 1 except for the catalyst amount,
Table 6 shows the results of determining the relationship between the amount of catalyst, the physical properties of the foam, and the state of the foam. Comparative Examples 12 to 17 - Test of Catalyst Amount - Formation was carried out in the same manner as in Comparative Example 1 except for the catalyst amount, and the results of determining the relationship between the catalyst amount, foam physical properties, and foam state are shown in Table 7. Stream side 19 to 23 Comparative examples 18 to 21 - Mold temperature range test 1 Forming was carried out under the same conditions as in Example 2 and Comparative Example 1, with only the mold temperature at the time of raw material injection being changed. The obtained foam was further cut to examine its appearance and only the state of the core was examined, and the results are shown in Table 8. Examples 24 to 25, Comparative Example 22 - Cure Test - Forming was carried out under the same conditions as Examples 2 and 17 and Comparative Example 1, only the curing time was changed. Table 9 shows only the state of the foam when it was removed from the mold. Examples 26 to 29 Comparative Example 23 - Bubble stabilizer mixing test Except for the type and amount of the bubble stabilizer, foaming was carried out in the same manner as in Example 1, and the foam physical properties and foam state were examined, and the results are shown in Table 10. Indicated. Example 30 and Comparative Example 24 - Moldability test - Using a foaming machine, a moldability test was carried out by replacing the foaming mold with a complex mold type in which it is difficult to obtain the best form, and the defect rate of the obtained foam was determined. The results are shown in Table 11. The following can be seen from the results in Tables 4 to 11. (+) Form physical properties Examples 1 to 10. Comparative Examples 1 to 11 (Tables 4 and 5) Among the examples according to the present invention, when no polymer polyol was blended, the hardness was 4 to 5 kg lower, and the compression set (especially wet set) was extremely 1 gI. you can get
CFC-free or the use of CFCs can be significantly reduced2
Furthermore, lower density is also possible. The wet set value in the example of the low density formulation is 35K in core density value according to the prior art.
It corresponds to g/113. Moreover, when a polymer polyol is blended, a high hardness foam can also be obtained. (2) Catalyst amount control range Examples 11 to 18, Comparative Examples 12 to 17 (Tables 6 and 7) It can be seen that the method of the present invention is incomparably wider than the conventional method. (3) Mold temperature control range Examples 19 to 23. Comparative Examples 18 to 21 (Table 8) The conventional method is limited to after 40"C#, whereas the method of the invention in 1. gives good results over a wide temperature range of 30 to 60°C. (4) Curing properties Examples 24 to 25. Comparative Example 22 (Table 9) In the example of the present invention, demolding can be done in about 1/2 the time compared to the conventional method, speeding up the process. (5 ) Moldability (Yield) Example 30, Comparative Example 24 (Table 11) While the conventional method resulted in approximately half of the forms having some kind of defect, the method of the present invention resulted in a defective rate of only 3% or less. , was extremely excellent. (Hereinafter in the margin) Table 1 Preparation table of polyether polyol (PEPO)
1 Preparation of polyether polyol (PEPO) 0 sets l
Preparation of polyether polyol (PEPO) Table 2 Preparation of mixed polyethyl polyol (PEPQ-: ×) Table 3 Preparation table of foam stabilizer 4 Form properties (1) Note) ■: Very good O: Good Δ: Slightly poor Physical properties (1) G ship note] ■ = Very good ○: Good Slightly poor ×, Poor × × Totally poor Wet set: 50°C 95R for 22 hours Table-5 Form physical properties (2) Table-6 Catalyst amount test table- 6 Catalyst amount test table-5 Form physical properties (2) G table-7 Catalyst amount test table-8 Mold temperature range test table-9 Cure test 0 mark O mark △ mark × mark × × mark Very good removability from the mold Very good removability from the mold Very little skin adhered to the mold Considerable amount of skin adhered to the mold Skin fully adhered to the mold/impossible to mold Table-11 Moldability Test Table 10 Bubble Stabilizer Mixing Test [Effects of the Invention] The method of the present invention breaks the common sense in the industry that compression set (especially wet set) worsens when the left foam position is lowered, and improves the compression set. It becomes possible to produce good low density flexible polyurethane foam. In addition, those with good cure link properties have high hardness, narrow catalyst width and mold temperature width,
Moreover, it broke the conventional wisdom that the product yield would decrease, resulting in an emergency situation.
Forms with good physical properties can be produced stably in a short period of time. Furthermore, since a soft foam can be obtained without using fluorocarbons, it can also contribute to environmental conservation. On the other hand, if a polymer polyol is used as the polyhydroquine compound, it is possible to increase the hardness, and a wide range of physical properties can be obtained depending on the compounding composition, so that it can be used in a wide range of applications. Patent applicant Daiichi Kogyo Seiyaku Co., Ltd.

Claims (1)

[Claims] A polyhydroxy compound and a polyisocyanate compound,
In the method of producing flexible polyurethane foam by reacting in the presence of a catalyst, a blowing agent, and a foam stabilizer, A. As a polyhydroxy compound, hydroxyl value 35 to 75 mgKOH/g Ethylene oxide content 25 to 60% by weight based on total OH groups , using a mixed polyether polyol or a modified product thereof satisfying 40 mol% or more of terminal primary OH groups; B. a compound represented by the following formula as a foam stabilizer {[Y(
R_2SiO)aR_2SiYO][Q]}b [wherein R represents a monovalent hydrocarbon group containing no aliphatic unsaturation. Y represents a divalent organic group. a represents an integer of 6 or more. Q is (C_2H_4O)y^1, (C_3H_6O)y
Indicates an oxyalkylene group consisting of ^2 alone or a combination thereof. When y^1 and y^2 are the oxyalkylene group alone,
Each represents an integer of 4 or more, or when the oxyalkylene group is a combination of two types, each is an integer of 1 or more, and the sum of the numbers y^1+y^2 is 4 or more. b represents an integer of 4 or more. ] is used in a proportion of 0.3 parts by weight or more per 100 parts by weight of the mixed polyether polyol.