JP3306718B2 - Method for producing polyurethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an improved polyurethane foam.

[0002]

2. Description of the Related Art When producing polyurethane foam,
The use of water as the blowing agent is well known. However, when foaming is performed using water alone, internal heat generation becomes remarkable due to the reaction between water and isocyanate, which may cause scorch. In particular, this phenomenon becomes more intense as the amount of water increases. In such a case, the foam not only significantly lowers the commercial value, but also causes a fire in extreme cases. Therefore, in order to avoid the above-mentioned phenomenon, a method of avoiding scorch by using a low-boiling solvent or freon together with water as a foaming agent has been adopted. However, avoiding scorch using freon or a low-boiling organic solvent has been restricted in recent years from the viewpoint of pollution and environmental pollution. Therefore, countermeasures against this are urgently required.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to a method for producing a polyurethane foam which has solved the above-mentioned drawbacks of the conventional method for producing a polyurethane foam, substantially does not use freon or a low boiling point solvent, and avoids scorch. The purpose is to provide.

[0004]

According to the present invention, an organic polyisocyanate and a polyol (provided that the number of functional groups is 2 or more)
In the above, the molecular weight per hydroxyl group is 800 to 1700.
And a polyether polyol having three or more functional groups and water
Polyether having a molecular weight of 300 to 800 per acid group
And the hydroxyl value represented by the following general formula (1) is 224-3.
At least one of an alkylene oxide adduct of an aliphatic monohydric alcohol of 19 mg KOH / g and an alkylene oxide adduct of an aromatic monohydric alcohol having a hydroxyl value of 286 to 407 mg KOH / g represented by the following general formula (2) And, if necessary, in the presence of a reticulating agent, a catalyst, and other auxiliaries.

## STR1 ## R1-O (AO) nH ( 1) (R1: alkyl group having 1 to 6 carbon atoms or an alkenyl group AO: ether groups derived from ethylene oxide and up
B ethers derived based mixtures or propylene oxide with ethers derived group from propylene oxide, n: number corresponding to the hydroxyl value)

Embedded image (R ₂ : hydrogen or an alkyl group having 1 to 3 carbon atoms B: an alkylene group having 1 to 3 carbon atoms AO: an ether group derived from an alkylene oxide having 2 to 4 carbon atoms. May be randomly added. Q: 0 or 1 m: a number corresponding to the hydroxyl value)

The present inventors have conducted intensive studies in view of the current situation. As a result, in the production of polyurethane foam, the use of a polyol and the above-mentioned specific alkylene oxide adduct as active hydrogen components has no pollution problem. It has been found that polyurethane foams that avoid scorch can also be produced.

Hereinafter, the present invention will be described in detail. The hydroxyl value used in the present invention is 224 to 319 mgKOH / g.
The alkylene oxide adduct of an aliphatic monohydric alcohol of the formula (I) is obtained by adding a specific alkylene oxide to a monoalkyl (alkenyl) ether of an aliphatic monohydric alcohol or a polyalkylene glycol, and The alkylene oxide adduct of an aromatic monohydric alcohol having a valence of 286 to 407 mgKOH / g is an aromatic monohydric alcohol, a mono (alkyl) phenyl ether of a polyalkylene glycol, or a mono (alkyl) phenylalkyl of a polyalkylene glycol. Each of them can be produced by adding an alkylene oxide to an ether.

Specific examples of the aliphatic monohydric alcohol include:
Methanol, ethanol, 1-propanol, 1-butanol, 2-butanol isobutyl alcohol, ter
t-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-betanol, neopentyl alcohol, -Hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-
1-butanol, allyl alcohol, and the like.
The compound has an alkyl or alkenyl group having 1 to 6 carbon atoms.

Specific examples of the monoalkyl (alkenyl) ether of polyalkylene glycol include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether. And tripropylene glycol monomethyl ether.

Specific examples of the aromatic monohydric alcohol include phenol, o-cresol, m-cresol and p-cresol.
-Cresol, p-ethylphenol, p-propylphenol, 2-phenoxyethanol, 2-phenoxy-i-propanol, 2-phenoxy-n-propanol, 2-p-methylphenoxyethanol, benzyl alcohol, α-methylbenzyl alcohol, p -Methylbenzyl alcohol and the like.

Examples of the mono (alkyl) phenyl ether of polyalkylene glycol include diethylene glycol monophenyl ether, dipropylene glycol monophenyl ether, triethylene glycol monophenyl ether, diethylene glycol mono-p-methylphenyl ether and the like.

The mono (alkyl) phenylalkyl ether of polyalkylene glycol includes diethylene glycol monobenzyl ether, dipropylene glycol monobenzyl ether, diethylene glycol mono-benzyl ether.
p-methylbenzyl ether and the like. These alcohols can be used alone or in combination of two or more.

[0012] In said alkyleneoxy de is e Chile <br/>N'okishido, propylene oxide is used. These alkylene oxides may be used alone or in combination of two kinds.
In the latter case, block addition, random addition, or a mixture of both may be used. The number of moles of alkylene oxide added is not particularly limited as long as the above-mentioned hydroxyl value is satisfied.

The alkylene oxide adduct of an aliphatic monohydric alcohol has a hydroxyl value of 224 to 319 mgKOH / g,
The hydroxyl value of the alkylene oxide adduct of the aromatic monohydric alcohol is 286 to 407 mgKOH / g .
When the hydroxyl value of the alkylene oxide adduct of an aliphatic monohydric alcohol and the hydroxyl value of the alkylene oxide adduct of an aromatic monohydric alcohol are lower than the above ranges , the viscosity of the mixture does not decrease and the resulting foam is uniform. Disappears.

The amount of the alkylene oxide adduct is 1 to 30% by weight, preferably 5 to 20% by weight, based on the polyol. If the amount is less than 1% by weight, a sufficient effect of compounding is not recognized. If the amount is more than 30% by weight, the viscosity is too drastically reduced, and the resulting foam is too soft.

As the polyol used in the present invention, all known at least bifunctional polyols can be used.
Specifically, ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, 1,3-butylene glycol, tetramethylene glycol, glycerin, sorbitol, sucrose, bisphenol A, ethylenediamine, diethylenetriamine, piperazine, ethanolamine, propanolamine, etc. Those obtained by adding ethylene oxide, propylene oxide or styrene oxide to one or more of the above, for example, a polyol having a number average molecular weight of 3000 in which propylene oxide is added to glycerin, and a number average obtained by adding propylene oxide to propylene glycol. A polyol having a molecular weight of 2,000, a polyol having a number average molecular weight of 500 obtained by adding propylene oxide to pentaerythritol, The number-average molecular weight obtained by adding de 80
0 polyol or the like can be used alone or in combination.

As the polyisocyanate that can be used in the present invention, all known at least bifunctional polyisocyanates can be used. For example, 2,4- or 2,6-tolylene diisocyanate, ortho toluidine diisocyanate, naphthalene diisocyanate, xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide-modified MDI, polymethylphenyl isocyanate, etc., alone or in combination Can be used.

In the present invention, the chemical equivalent ratio of isocyanate to active hydrogen (isocyanate index) is 10
The number is preferably from 0 to 130, but is not particularly limited. Further, the foaming agent, catalyst, foam stabilizer and, if necessary, flame retardant, pigment, filler and the like are not particularly limited, and all of those used for ordinary flexible polyurethane foams and rigid polyurethane foams can be used. .

The flexible and rigid polyurethane foam of the present invention is produced by a conventional one-shot method using the above-mentioned raw materials. As a molding method, a slab molding method is appropriate. A prepolymer method is also possible, but not limited thereto.

[0019]

EXAMPLES The present invention will be described specifically with reference to Examples.
The present invention cannot be limited to these. [Operation procedure] After blending each mixture (liquid B) except for isocyanate at 4000 rpm for 30 seconds and homogenizing the mixture, the viscosity was measured with a B-type viscometer to confirm the effect of the viscosity reducing agent of the compound of the present invention. After stirring again for 30 seconds, a predetermined amount of isocyanate (crude MDI: diphenylmethane diisocyanate, index 1.05 content 31% by weight) was quickly added, and the mixture was further stirred for 10 seconds. After mixing, the mixture was poured into an aluminum box, and the foaming state (cream time, rise time, tack-free time) was observed. Take out after leaving for 24 hours, observe the appearance of the obtained foam, the occurrence of scorch, measure the density and closed cell rate,
The properties of the foam were confirmed. (1) Cream time Time after the mixing is completed, until the mixture foams and becomes a cloudy creamy liquid, and immediately before the liquid starts to expand. (2) Rise time The creamy liquid expands and grows into a foamy substance,
Time to complete inflation. (3) Tack free time The time from the end of rise to the completion of the surface effect as a foam. (4) Appearance of foam Uniform foam state: ○ Non-uniform foam state: × (5) Density JIS A 9514 “Rigid urethane foam heat insulating material”
(6) Closed cell rate ASTM D 2856 "OPEN CEL CONTE
NT OF RIGID CELLULLAR PLASTI
Compliant with "CS BY THE AIR PYCNOMETER"

[Production Example] Alkylene oxide was added at 120 ° C. using 0.2% KOH (relative to the starting alcohol) as a catalyst to obtain Products A to I of the present invention. A: Compound obtained by adding P03 mole to 1 mole of butanol (hydroxyl value 226 mgKOH / g) B: P02 mole added to 1 mole of ethyl carbitol
(Hydroxyl value 224 mgKOH / g) C: P02 mol addition to 1 mol of n-propyl alcohol (hydroxyl value 319 mgKOH / g) D : P02 mol addition to 1 mol of butyl cellosolve
(Hydroxyl value 240mgKOH / g) E : E01 mol addition to 1 mol of phenol (hydroxyl value 407m
gKOH / g) F : Addition of P01 mole to 1 mole of phenol (hydroxyl value 369m
gKOH / g) G : Addition of E01 mol to 1 mol of p-cresol (hydroxyl value)
H : Addition of P01 mol to 1 mol of phenoxyethanol (hydroxyl value: 286 mgKOH / g) I : E01 mol addition to 1 mol of benzyl alcohol (hydroxyl value: 369 mgKOH / g)

Example 1 Propylene oxide was added to 100 parts by weight of a sorbitan-based polyol (having a hydroxyl value of 550), and 3 moles of propylene oxide were added to 1 mole of butanol.
The molar ratio of the alkylene oxide adduct (product A of the present invention) was 10 parts by weight, the urethane-forming catalyst triethylenediamine 1.5 parts by weight, the silicone-based activator 1.5 parts by weight, and water 6.5 parts by weight. And a predetermined amount of isocyanate was quickly added and stirred to obtain a polyurethane foam. Table 1 shows the state of the scorch and the appearance of the foam.

[Examples 2 to 8 ] Polyurethane foam was prepared in the same manner as in Example 1 except that a sucrose-based polyol (hydroxyl value: 451) and an alkylene oxide adduct (Products B to I of the present invention) shown in Table 1 were used. Was manufactured. Table 1 shows the foamability at the time of production, the state of the scorch of the obtained polyurethane foam, and the physical properties of the foam.

Comparative Example Sucrose polyol (having a hydroxyl value of 4)
A polyurethane foam was produced in the same manner as in Example 1 except that the alkylene oxide adduct was not used, except that the above (51) was used. Table 1 shows the foamability at the time of production, the state of the scorch of the obtained polyurethane foam, and the physical properties of the foam.

[0024]

[Table 1]

[0025]

As is clear from the examples and comparative examples,
The present invention relates to a method for producing a polyurethane foam,
As the active hydrogen component, the polyol and the hydroxyl value are 150
an alkylene oxide adduct of an aliphatic monohydric alcohol having a mgKOH / g or more, or a hydroxyl value of 170 mgKOH
/ G or more of an alkylene oxide adduct of an aromatic monohydric alcohol, the viscosity of the active hydrogen component mixture (solution B) is reduced, and a uniform foam is obtained.
In addition, there is an effect that there is no problem such as pollution and environmental pollution and scorch can be avoided.

Continuation of the front page (56) References JP-A-4-146916 (JP, A) JP-A-50-46798 (JP, A) JP-A-61-19618 (JP, A) JP-B-42-678 (JP) , B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (2)

(57) [Claims] 1. A method for producing a polyurethane foam using water as a blowing agent without substantially using a low-boiling organic solvent, comprising the steps of:
And the number of functional groups is 2 or more, and the molecular weight per hydroxyl group is 8
Polyether polyol having a molecular weight of from 0 to 1700,
The number of groups is 3 or more, and the molecular weight per hydroxyl group is 300 to 8
Excluding the use of a mixture of polyether polyols
And at least one alkylene oxide adduct of an aliphatic monohydric alcohol having a hydroxyl value of 224 to 319 mgKOH / g represented by the following general formula (1 ) , and A method for producing a polyurethane foam, comprising reacting in the presence of an agent, a catalyst, and other auxiliaries. Embedded image R1-O (AO) nH (1) (R1: an alkyl or alkenyl group having 1 to 6 carbon atoms, AO: a mixture of an ether group derived from ethylene oxide and an ether group derived from propylene oxide Or an ether group derived from propylene oxide, n: a number corresponding to the hydroxyl value) 2. A method for producing a polyurethane foam using water as a foaming agent without substantially using a low-boiling organic solvent, comprising the steps of:
And the number of functional groups is 2 or more, and the molecular weight per hydroxyl group is 8
Polyether polyol having a molecular weight of from 0 to 1700,
The number of groups is 3 or more, and the molecular weight per hydroxyl group is 300 to 8
Excluding the use of a mixture of polyether polyols
And at least one alkylene oxide adduct of an aromatic monohydric alcohol having a hydroxyl value of 286 to 407 mgKOH / g represented by the following general formula (2 ) , and A method for producing a polyurethane foam, comprising reacting in the presence of an agent, a catalyst, and other auxiliaries. Embedded image (R ₂ : hydrogen or an alkyl group having 1 to 3 carbon atoms B: an alkylene group having 1 to 3 carbon atoms AO: an ether group derived from an alkylene oxide having 2 to 4 carbon atoms. May be randomly added. Q: 0 or 1 m: a number corresponding to the hydroxyl value)