JPS61268716A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain the titled non-flexible product of both high air-permeability and dimensional stability, by reaction of a polyol component, i.e. a combination of both low-molecular weight and high-molecular weight polyols in the presence of water, urea compound and solid sugar. CONSTITUTION:The objective product can be obtained by reaction of (A) 100pts. wt. of a polyol component, i.e. a combination of both low-molecular weight and high-molecular weight polyols, in combination with (B) >=1pt.wt. of urea compound (pref. urea) and/or solid sugar (pref. sucrose) and (C) >=2pts.wt. by water as a foaming agent, with (D) an organic polyisocyanate, in the presence of, if needed, catalyst and other ingredient(s). Preferably, said low-molecular weight polyol is of OH-value 200-600, whereas said high-molecular weight polyol 24-56.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a method for producing polyurethane foam, and more particularly to a method for producing non-flexible polyurethane foam with excellent air permeability and dimensional stability.

(Prior Art) Conventionally, methods for improving the air permeability of non-flexible polyurethane foam include (1) using a catalyst that promotes the gasification reaction, and (2) using a silicone surfactant with strong foam-breaking properties. Are known. In method (1), it is difficult to balance the reaction, such as when the amount of the gasification promoting catalyst is too large, the polyurethane foam collapses, and when it is too small, the air permeability deteriorates and shrinkage occurs. Method (2) has the disadvantage that the cells tend to become rough and it is difficult to obtain fine and uniform polyurethane foam.

(Object of the invention) The present invention aims to provide a non-flexible polyurethane foam with excellent air permeability.

(Structure of the Invention) The present invention deals with the production of polyurethane foam by reacting a polyol and an organic polyisocyanate in the presence of a blowing agent and, if necessary, a catalyst and other additives. A2) is used in combination with (B) 1 part by weight or more of a urea compound (B1) and/or solid carbohydrates (B2) and (C) 2 parts by weight or more of water per 100 parts by weight of polyol. The present invention relates to a method for producing non-flexible polyurethane foam, which is characterized by the following.

In the present invention, it is essential to use a low molecular weight polyol (A1) and a high molecular weight polyol (A2) in combination. (A1) is usually a polyol with a hydroxyl value of 100 to 1,850, preferably 150 to 1,000. Particularly preferably from 200 to 600. (A2) is usually a polyol with a hydroxyl value of 70 or less, preferably 20 to 60. Particularly preferably from 24 to 56. When a low molecular weight polyol is used alone, the air permeability of the resulting polyurethane foam deteriorates, making it difficult to obtain a polyurethane foam with low density. On the other hand, when a high molecular weight polyol is used alone, the physical strength of the resulting inflexible foam decreases, making it difficult to obtain the required strength when made into a low-density polyurethane foam. Furthermore, since a mixture of high molecular weight polyol and water tends to form a highly viscous gel-like substance, it is difficult to mold a uniform foam. (However, in the case of high molecular weight polyols with a high ethylene oxide content, it is difficult to form a gel, but it is difficult to balance the reaction, and it is difficult to obtain strength.) (A1) and (A2), respectively. Polyether polyols and/or polyester polyols having hydroxyl numbers in the above range can be used.

Examples of polyether polyols include compounds having a structure in which alkylene oxide is added to a polyfunctional compound containing an active hydrogen atom, such as polyhydric alcohol, amines, polyhydric phenol, and polycarboxylic acid. The above polyhydric alcohols include ethylene glycol, propylene glycol,
1,4-butanediol, 1,6-hexanediol,
Dihydric alcohols such as diethylene glycol and neopentyl glycol, and trihydric or higher polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, diglycerin, sorbitol, and sucrose.Amines include monoamines such as ammonia and butylamine. , ethylenediamine, trimethylenediamine,
Aliphatic polyamines such as diethylenetriamine, heterocyclic polyamines such as piperazine and N-aminoethylpiperazine; alicyclic polyamines such as dicyclohexylmethanediamine and isophoronediamine; phenylenediamine, tolylenediamine, diethyltolylenediamine, xylylenediamine, Aromatic polyamines such as diphenylmethanediamine and polyphenylmethane polyamine; alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; polyhydric phenols include polyhydric phenols such as pyrogallol and hydroquinone, as well as bisphenols such as bisphenol A. Examples of polycarboxylic acids include aliphatic polycarboxylic acids such as succinic acid and adipic acid, and aromatic polycarboxylic acids such as phthalic acid, terephthalic acid and trimellitic acid. Two or more kinds of the above-mentioned active hydrogen atom-containing compounds can also be used. Examples of the alkylene oxide to be added to the active hydrogen atom-containing compound include ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), butylene oxide, tetrahydrofuran, styrene oxide, epichlorohydrin, and the like. Alkylene oxide may be used alone or in combination of two or more, and in the latter case, block addition (chip type,
(balanced type, active secondary type, secondary type, etc.), random addition, or a mixture of both (chip after random addition). Preferred among these alkylene oxides are tetrahydrofuran, PO and/or EO. The addition of alkylene oxide can be carried out in the usual manner, either without catalyst or in the presence of a catalyst (alkali catalyst, amine catalyst, acidic catalyst) (particularly in the latter stages of alkylene oxide addition) at normal pressure or It is carried out under pressure.

Examples of polyester polyols include condensed polyester polyols obtained by reacting polyols (low-molecular-weight polyols and/or polyether polyols) with dicarboxylic acids, and polyester polyols obtained by ring-opening polymerization of lactones. Examples of the low-molecular polyol include diols such as ethylene glycol, propylene glycol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, bis(hydroxymethyl)cyclohexane, bis(hydroxyethyl)benzene; trimethylolpropane, glycerin, etc. A mixture thereof is mentioned. Examples of dicarboxylic acids include succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, dimer acid, and mixtures thereof. Examples of the lactone include ε-caprolactone.

In addition, as at least a part of (A1), polyhydric alcohols (e.g., ethylene glycol, diethylene glycol, trimethylolpropane, etc.), alkanolamines (e.g., triethanolamine, jetanolamine, etc.), which are the starting materials for polyether polyols and polyester polyols, may be added. etc.) can also be used.

Furthermore, other polyols such as polybutadiene polyols and acrylic polyols can also be used as at least a portion of (A1) and (A2).

In the present invention, (A1) and (A2) are each 2
More than one species may be used in combination. For example, as (A1) or/and (A2), an amine polyol and a non-amine polyol (
Polyhydric alcohols, etc.) used in combination with polyols, and those with different hydroxyl values (e.g. 700 or higher and 50 or higher)
0 or less, 200 or more, and less than 200)
combinations, combinations of those with different numbers of functional groups (for example, those with 2 to 4 valences and those with 6 to 8 valences), those with terminal hydroxyl groups [
Examples include the combination of chip type, balanced type, random chip type, etc., with -grade hydroxyl group content: e.g. 20 to 100%] and terminal secondary hydroxyl group type (PO single adduct, random adduct, active secondary type, etc.). It will be done.

In the present invention, polyol [CA1) and/or (
A2. ) ] may be a so-called polymer polyol modified with an ethylenically unsaturated monomer. Examples of monomers used in the production of polymer polyols include those described in Japanese Patent Application No. 59-64209. Among them, preferred are acrylonitrile, methyl methacrylate, styrene, and butadiene. Particularly preferred is acrylonitrile, or a combination of acrylonitrile and styrene (styrene:acrylonitrile weight ratio of 10:90 to 60:40). Polyols include polyols that are partially modified with monomers [for example, modified (A1), unmodified (A1), and modified (A1).
) and native (A2) or native (A1)
and modified (A2)], or all of them may be modified. It may also be a mixture of (A1) and (A2) modified with a monomer. The proportion of monomers used for modification can be varied over a wide range, but polyol 100
2 to 70 parts, preferably 5 to 40 parts, of the ethylenically unsaturated monomer (or polymer). Modification of a polyol with an ethylenically unsaturated monomer (production of a polymer polyol) can be carried out by a conventional method. For example, a method of polymerizing an ethylenically unsaturated monomer in a polyol in the presence of a polymerization catalyst (such as a radical generator) (US Pat. No. 3,383,351,
JP-B No. 39-24737, JP-B No. 47-47999, JP-A-50-15894) or a polymer obtained by pre-polymerizing the above monomers and polyol in the presence of a radical generator. Method of making
No. 597). The former method is preferred. Polymerization catalyst (radical generator) used in polymerization reaction
As such, azo compounds, peroxides, persulfates, perborates, etc. can be used, and azo compounds are practically preferred.

The amount used is also not particularly limited, and for example, 0.00 parts per 100 parts of the ethylenically unsaturated monomer (or polymer).
The amount is 1 to 20 parts, preferably 0.1 to 15 parts. The above polymerization can also be carried out in the presence of a solvent such as toluene or xylene. The reaction temperature is usually 50-170℃,
Preferably it is 90-150°C.

In addition to (A1) and (A2), other polyols [those having a hydroxyl value intermediate between (A1) and (A2)], other active hydrogen atom-containing compounds such as polyamines (such as polyethers) may be used as necessary. Those listed as raw materials and their alkyl, alkoxy or halogen substituted products, etc.), polyether polyamines, amino alcohols (ethanolamine, propatoolamine, etc.), dicarboxyl group-containing polybutadiene, etc. can also be used in combination.

In the present invention, the amounts of (A1) and (A2) to be used can be varied.
1) is usually 10 to 70 parts, preferably 20 to 60 parts, (
A2) is usually 30 to 90 parts, preferably 40 to 80 parts.

In the present invention, the average hydroxyl value of the polyols [(A1), (A2), and other polyols if necessary] is usually 40 to Boo, preferably 60 to 500. In the case of rigid foam production, it is usually 300 or more, half For hard materials, it is usually 300 or less.

The average number of functional groups of the polyol is usually 2 to 8, preferably 3 to 6. The (average) number of functional groups in (A1) is usually 2-8, preferably 3-6, and the (average) number of functional groups in (A2) is usually 2-6, preferably 2-4.

In the present invention, specific examples of the urea compound (B1) used as an essential component along with (A1) and (A2) include urea; and its hydrocarbon groups (alkyl, cycloalkyl, aryl, aralkyl, alkaryl) Substituted substances such as methylurea, ethylurea, phenylurea,
Examples include benzyl urea, tolylurea, and the like.

Urea is particularly preferred.

In the present invention, as the solid carbohydrate (B2) used together with or in place of the urea compound (B1), carbohydrates that are solid at 20°C can be used, and specific examples thereof include monosaccharides such as Glucose, mannose, sorbose, galactose, fructose, disaccharides such as sucrose, maltose,
Examples include milk sugar (lactose), sugar derivatives such as sugar alcohols such as sorbitol, and glucosides such as methyl glycoside. These can be used alone or as a mixture.

Among these, carbohydrates having a solubility of 50 parts or more per 100 parts of water at 20°C are preferred, and sucrose, high fructose sugar, sorbitol, or a mixture thereof are particularly preferred.

(B) The amount of [(B1) and/or (B2)] used is usually 1 part or more per 100 parts of polyol,
Preferably it is 2 to 20 parts, particularly preferably 3 to 10 parts. If the amount is less than 1 part, the resulting polyurethane foam will not have sufficient air permeability. (B) is preferably used by dissolving it in a polyol in the presence of water, but it can also be used in a dispersed state in an amount greater than the soluble amount.

The urea compound (B1) and carbohydrates (B2) can be used alone or in a mixture. When (B1) and (B2) are mixed, the weight ratio of (at):(B2) is 90:10 to 50:50, preferably 8
0: 20-60: 4G.

In the present invention, the amount of water (C), which is another essential component, is usually 2 to 50 parts per 100 polyols.
Preferably it is 3 to 40 parts, particularly preferably 6 to 30 parts. If the amount is less than 2 parts, breathability will be insufficient.

Moreover, if it exceeds 50 parts, the obtained polyurethane foam tends to collapse, which is not preferable.

As the organic polyinsyanate used in the present invention, those conventionally used in the production of polyurethane can be used. Specific examples of these include JP-A-57-2
Compounds described in Publication No. 322 can be used. Among these, preferred are aromatic polyinsyanates, such as TDI, MDI: Their crude polyisocyanates, such as crude TDI, crude MDI (polyphenylmethane polyisocyanate, so-called polymeric MDI) > [crude diaminophenylmethane (formaldehyde and aromatic amine or a condensation product with a mixture thereof; a phosgenated product of a mixture of diaminodiphenylmethane and a small amount (for example, 5 to 20% by weight) of a trifunctional or higher functional polyamine: polyallyl polyisocyanate (PAP1)]; and a modified polyinsyanate, such as a liquid MDI (carposiimide modification, trihydrocarpyl water sulfate modification, etc.): and combinations of two or more of these (for example, a combination of crude@MDI and/or crude 1B+TDI with modified polyisocyanate and/or pure polyisocyanate). Among these, more preferred are TDI, MDI and especially crude MDI.

In carrying out the present invention, the ratio of the active hydrogen-containing compound containing a polyol and the organic polyisocyanate can be varied, but the equivalent ratio of the active hydrogen-containing group of the active hydrogen-containing compound to the NGO group of the organic polyisocyanate is usually 1. .0: 0.3-1.0=1.2, preferably 1.
The ratio is 0:0.4 to 1.0:1.0. However, the active hydrogen of the urea compound is excluded from this equivalent calculation. In addition, the proportion of NGO groups may be increased from the above (equivalent ratio, for example, 1.0: 1.2 to 1.0).
: 50) It is also possible to produce polyisocyanurate foams.

In the present invention, as a blowing agent, a low boiling point organic compound such as halogen-substituted aliphatic hydrocarbons (Freons such as Freon-11) may be used in combination with water (C) if necessary. The amount of halogen-substituted aliphatic hydrocarbons to be used can be selected depending on the predetermined density (free density 6 to 50! j/rd, especially 6 to 20 knots/TIt),
It is usually 0 to 100 parts, preferably 10 to 70 parts per 100 parts of polyol.

In the present invention, a small amount (0.01 to 10 parts per 100 parts of polyol) of a catalyst can be used if necessary.

Typical examples include amine catalysts, metal catalysts,
and combination systems thereof. As an amine catalyst,
Trimethylamine, dimethylbenzylamine, N-ethylmorpholine, N-methylmorpholine, triethylenediamine and its formate, dimethyl- or diethyl-
Amine ethanol, dimethylpiperazine, 1,2-dimethylimidazole, di- or triethanolamine, 1,8-diazabicyclo(5,4,0)undecene-
7 and its phenol salts. Examples of the metal catalyst include dibutyltin dilaurate, stannous octoate, lead octylate, and the like.

As other additives that can be used as necessary in the present invention, a polysiloxane-polyoxyalkylene block copolymer as a foam stabilizer is important.

In addition, other additives such as colorants (dyes, pigments), plasticizers, extenders, fillers, flame retardants, stabilizers and the like may also be used if necessary.

The manufacturing method for polyurethane foam can be the same as before.
For example, “Polyurethane J (published by Maki Shoten in 1960)
It can be carried out by the method described in "Polyurethanes: Chemistry and Technology, Part Echemistry J" (published by Interscience Publishers, 1962).Both the one-shot method and the prepolymer method can be applied. Combination of both (e.g. crude MDI
and a prepolymer) can also be used. The free isocyanate group content of the prepolymer is usually 10 to 40
%, preferably 15-35%, particularly preferably 20-3
It is 0%.

In the present invention, non-flexible foam means something other than flexible foam, and includes rigid foam, semi-rigid foam, and semi-flexible foam.

(Example) The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Example 1 92 parts of glycerin, 2308 parts of PQ, then [:QB
00 parts of polyether polyol (I>50 parts and pentaerythritol 13
6 parts of urea was added to 50 parts of polyether polyol (I1) with a molecular weight of 400, which was obtained by adding 264 parts of pQ to 6 parts of pQ.
5 parts, 760 parts of water, 1.2 parts of silicone 5H-193 (silicone foam stabilizer manufactured by Toray Silicone), DABCO 33L
V (Amishi touch TS manufactured by Sankyo Air Products) 1.2
Millionate HR-200 (Polymeric MDI manufactured by Nippon Polyurethane Industries, NGO content 30.5%) was added to a premix containing 13 parts of a blowing agent (Freon-11).
After adding 126 parts and stirring and mixing at a speed of 100 ORPH for 5 seconds, the mixture was poured into a wooden mold (length 50 x width 30 x thickness 5α) adjusted to a mold temperature of 35 to 40°C, the lid was closed, and foaming was performed within the mold. After 5 minutes had elapsed from stirring, the mold was removed and a panel form was created.

The closed foam rate and dimensional change rate of the obtained foam were measured. The closed cell ratio was in accordance with ASTHD-2856-70. The dimensional change rate is -30℃, 70℃×95%RH.

61% was measured under the condition of standing at 100° C. for 2 days.

Example 2 4258 parts of pQ to 92 parts of glycerin, then 606 parts
75 parts of a polyether polyol (II1) with a molecular weight of 15,000 obtained by addition polymerization of 50 parts, 68 parts of POB on 92,166 parts of Jiguria, and then 25 parts of a polyether polyol (IV) with a molecular weight of 1,000 obtained by addition polymerizing 60,166 parts with 75 parts of urea .0 parts, water 14 parts, silicone L-53
02 (silicone foam stabilizer manufactured by Nippon Unicar Co., Ltd.) 2.5 parts,
Polycat-17 (Amine catalyst manufactured by Sun Abbott) 5
．． 155 parts of Millionate) fR-200 was added to a premix containing 0 parts of foaming agent (Freon-11) and 26 parts of a foaming agent (Freon-11), a panel form was prepared in the same manner as in Example 1, and the physical properties were evaluated.

Example 3 In Example 2, the amount of water was changed to 26 parts, and the blowing agent Freon-
66 parts of 11, 2 parts of Millionate MR-200
A panel form was prepared in the same manner except for part 07, and the physical properties were evaluated.

Example 4 In Example 1, 3.5 parts of urea was replaced with 5.0 parts of sucrose.
parts, the amount of water was changed to 8.0 parts, silicone 5H-19
A panel form was prepared in the same manner using 1.5 parts of 3, 2.0 parts of 33LV, 21 parts of the blowing agent (Freon-11), and 150 parts of Millionate HR-200, and the physical properties were determined. We conducted an evaluation.

Example 5 A panel form was prepared in the same manner as in Example 4 except that 5 parts of sucrose was replaced with 5 parts of sorbitol, and the physical properties were evaluated.

The physical properties of the obtained polyurethane foam are as shown in Table 1, and it is excellent in closed cell ratio and air permeability with small dimensional change rate.

Table 1 Comparative Examples 1 and 2 Comparative Example 1 was obtained by removing only urea from Example 1, and Comparative Example 2 was obtained by removing only water from Example 1 and increasing the amount of Freon-11 to 80 parts. . A panel form was created using a similar method.

The polyurethane foams obtained in Comparative Examples 1 and 2 shrank significantly, and physical properties could not be measured. Furthermore, when observing the cell state of these foams with a magnifying glass, mirrors remain in most of the cells, indicating that they are closed cells.

(Effects of the Invention) By the method of the present invention, a non-flexible polyurethane foam with excellent air permeability can be obtained. In general, non-flexible polyurethane foam with a high closed cell ratio is 20Ky/rd.
At free densities below, the resin strength is low, so it cannot withstand the reduced pressure caused by cooling the gas trapped in the bubbles, and it tends to shrink at low temperatures, and the dimensional change rate increases under high temperature and high humidity conditions. There are limits to lower density. Since the polyurethane foam obtained by the present invention has high air permeability, it does not shrink at low temperatures and has a small dimensional change rate under high temperature or moist heat atmosphere.

Therefore, the polyurethane foam obtained by the method of the present invention can be used in applications that are exposed to high temperatures and high humidity, which have not been applicable up to now, as well as applications that require low density due to cost considerations. can be used. Specific applications include insulation for water heaters used at high temperatures, bathtub insulation fillers used under humid heat conditions, and packaging materials that require low density (free density 6 to 2 ONg/m) for economic reasons. characterized by usefulness

Claims (1)

[Claims] 1. When producing polyurethane foam by reacting a polyol and an organic polyisocyanate in the presence of a blowing agent and, if necessary, a catalyst and other additives, a low molecular weight polyol (A_1) and a high molecular weight polyol (A_2) is used in combination with (B) 1 part by weight or more of urea compound (B_1) and/or solid carbohydrate (B_2) and (C) 2 parts by weight or more of water per 100 parts by weight of polyol. A method for producing non-flexible polyurethane foam, characterized by: 2, (A_1) has a hydroxyl value of 100 or more,
The manufacturing method according to claim 1, wherein (A_2) has a hydroxyl value of 70 or less. 3. (A_1) in 10 to 70 parts by weight of polyol
The manufacturing method according to claim 1 or 2, wherein parts by weight are used. 4. Claims 1 to 3, in which (B_1) is urea
The manufacturing method described in any of paragraphs. 5. (B_2) is 50 parts by weight per 100 parts by weight of water at 20°C.
The manufacturing method according to any one of claims 1 to 4, wherein the saccharide has a solubility of at least part by weight. 6. The production method according to any one of claims 1 to 5, wherein (B_2) is sucrose, high fructose sugar, sorbitol, or a mixture thereof. 7. The manufacturing method according to any one of claims 1 to 6, wherein 3 to 10 parts by weight of (B_1) and/or (B_2) are used per 100 parts by weight of polyol. 8. The manufacturing method according to any one of claims 1 to 7, wherein 6 to 30 parts by weight of (C) is used per 100 parts by weight of polyol. 9. The ratio (equivalent ratio) of the active hydrogen-containing compound containing polyol [excluding (B)] and the organic polyisocyanate is 1.
Claim 1 which is 0:0.4 to 1.0:1.0
The manufacturing method according to any one of items 1 to 8. 10. The manufacturing method according to any one of claims 1 to 9, wherein the organic polyisocyanate is polyphenylmethane polyisocyanate.