JPH0710958A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To produce a polyurethane foam which is industrially useful, uniform and reproducible, and almost free from foam defects by utilizing a lignocellulosic substance. CONSTITUTION:A reaction soln. contg. a liquefied lignocellulosic substance and obtd. by reacting a lignocellulosic substance with a polyhydric alcohol in the presence of an acid catalyst is neutralized with a compd. having a tert. amine structure and optionally contg. an alkali metal hydroxide and/or an alkaline earth metal hydroxide and then reacted with a polyisocyanate in the presence of a blowing agent.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention liquefies a lignocellulosic material such as wood in the presence of a polyhydric alcohol and an acid catalyst, and has characteristics such as low combustion calorific value and biodegradability and a uniform cell structure. The present invention relates to a method for producing a polyurethane foam.

[0002]

2. Description of the Related Art There is a method of utilizing a lignocellulosic material such as an unused material, a waste material, and a scrap material as a raw material of a polyurethane foam. When used as a raw material for polyurethane foam, the lignocellulosic material must be in liquid form. A liquefaction method is already known in Japanese Patent Laid-Open No. 4-106128, etc., but an acid catalyst such as sulfuric acid is used as a catalyst during liquefaction. If these acids remain, problems such as reaction delay occur during the production of the polyurethane foam, so it is necessary to neutralize these acids with a neutralizing agent. Conventionally, as the neutralizing agent, hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide and barium hydroxide have been used.

[0003]

Among the above-mentioned neutralizing agents such as hydroxides of alkali metals or alkaline earth metals, since these neutralizing agents exhibit a strong catalytic activity in the reaction for forming polyurethane, the neutralizing agents are The reactivity and moldability of the foam greatly differed depending on the amount added, and there was a problem in the uniformity and reproducibility of the resulting foam. An object of the present invention is to provide a polyurethane foam which has industrially useful uniformity, reproducibility, and few foam defects.

[0004]

Means for Solving the Problems As a result of intensive studies to solve such conventional problems, the present inventors have found that a compound containing a tertiary amine structure is used as a neutralizing agent for all or part of it. Therefore, they have found that a polyurethane foam having no foam defect can be easily obtained, and completed the present invention. That is, according to the present invention, a reaction liquid containing a liquefied lignocellulosic substance obtained by reacting a lignocellulosic substance and a polyhydric alcohol in the presence of an acid catalyst is treated with an alkali metal hydroxide and / or an alkaline earth metal hydroxide. The method for producing a polyurethane foam is characterized in that it is neutralized with a compound containing a tertiary amine structure which may contain a compound, and then reacted with a polyisocyanate in the presence of a foaming agent.

The liquefied lignocellulosic material of the present invention can be obtained, for example, by reacting a lignocellulosic material in the presence of an acid catalyst and a polyhydric alcohol by the method described in JP-A-4-106128. Examples of lignocellulosic materials include wood flour, wood fibers, wood chips and veneer waste,
Examples include paper such as straw, chaff, ground pulp, thermomechanical pulp, waste paper, and pulps. Specific examples of wood include citrus birch, sitka spruce, cedar, red pine, poplar, and lauan. The lignocellulosic material may be pretreated with halogen, for example (JP-A-63-179).
No. 61).

The polyhydric alcohols are dihydric or higher alcohols, examples of which include aliphatic polyhydric alcohols, polyether polyols, polyester polyols, and the like, with polyethylene glycol, glycerin and ethylene glycol being particularly preferred. Each of the polyhydric alcohols may be used alone, or two or more thereof may be appropriately mixed and used, and the polyhydric alcohol having a relatively large molecular weight and the polyhydric alcohol having a relatively small molecular weight are used in combination. Is preferred. Further, for the purpose of lowering the viscosity of the solution or facilitating the liquefaction / dissolution, one or more kinds of water or an organic solvent such as monohydric alcohol, acetone, ethyl acetate or the like from the beginning or during the liquefaction / dissolution. It is also possible to add and coexist. These organic solvents are usually added in an amount of preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyhydric alcohol. The liquefaction reaction is particularly carried out at normal pressure in the presence of an acid catalyst. The acid catalyst may be a mineral acid, an organic acid, or a Lewis acid, such as sulfuric acid, hydrochloric acid, toluenesulfonic acid, phenolsulfonic acid, aluminum chloride,
Zinc chloride and boron trifluoride are preferred. The reaction temperature is 100 to 200 ° C, preferably 150 to 160 ° C. The reaction liquid containing the liquefied lignocellulosic material is preferably used after filtering after the liquefaction reaction.

The liquefied lignocellulosic material of the present invention comprises:
If necessary, an active hydrogen group-containing compound can be added. The active hydrogen group-containing compound has a molecular weight of 200 to 10,000 used as a reaction partner of polyisocyanate.
Polyether polyol, polyester polyol,
Polycarbonate polyol or the like is used. Examples of the polyether polyol include a polymerization product of tetrahydrofuran, propylene oxide and / or ethylene oxide, a copolymer thereof, or a graft polymer with a vinyl monomer.

Examples of polyester polyols include those obtained from polyhydric alcohols and polycarboxylic acids by a known method. Examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, butylene glycol, hexamethylene glycol,
Examples include neopentyl glycol, 3-methylpentanediol, cyclohexanedimethanol, glycerin and trimethylolpropane. Examples of polyvalent carboxylic acids include succinic acid, adipic acid, sebacic acid, dimer acid, phthalic acid, phthalic acid alkyl esters, trimellitic acid, pyromellitic acid, maleic acid, fumaric acid, and itaconic acid. Further, those obtained by ring-opening polymerization of cyclic esters such as butyrolactone, valerolactone and caprolactone are also included. As the polycarbonate polyol, 1,6-hexanediol,
A polycarbonate diol obtained by transesterification of an aliphatic diol such as 1,4-cyclohexanedimethanol or an alicyclic diol with a cyclic carbonate such as a dialkyl carbonate, a diaryl carbonate or ethylene carbonate can be mentioned. It is also possible to use natural polyols such as polyols already containing urethane or urea groups, castor oil, tar oil, carbohydrates. The addition amount of these active hydrogen compounds is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the liquefied lignocellulosic material.

All the compounds containing a tertiary amine structure of the present invention can be used. For example, pyridine and derivatives of pyridine include picoline, lutidine, ethylpyridine, aminopyridine, pyridylcarbinol, pyridylethyl alcohol, acetylpyridine, vinylpyridine, mercaptopyridine, pyridylacrylic acid, and pyrimidine compounds include pyrimidine and aminopyrimidine. , Mitosine can be mentioned. Particularly preferably,
Pyridine and pyridimine compounds.

In the method for mixing the liquefied lignocellulosic material and the compound containing a tertiary amine structure of the present invention, the compound containing a tertiary amine structure may be added and mixed immediately after the production of the liquefied lignocellulosic material. Alternatively, a method in which an active hydrogen group-containing compound is added and then mixed after the production of the liquefied lignocellulosic material may be used. The addition amount of the compound containing a tertiary amine structure is an amount for neutralizing a part or all of the acid catalyst used in the production of the liquefied lignocellulosic material, and preferably 2 to 150% equivalent of the acid catalyst. The amount to neutralize. In addition, alkali metal such as sodium hydroxide and potassium hydroxide and / or alkaline earth metal such as magnesium hydroxide and calcium carbonate, primary amine and secondary amine should be partially used in combination for neutralization. You can also The neutralization in the present invention includes partial neutralization of the acid catalyst, and the pH after neutralization is in the range of 2-12.

Examples of the polyisocyanate used in the present invention include phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tetramethyl xylene diisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate and the like, and aromatic diisocyanates consisting of isomers thereof. , 6-hexamethylene diisocyanate, 1,1
Aliphatic diisocyanates such as 2-dodecane diisocyanate, cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, and the like can be mentioned. Further, an isocyanate group-terminated compound obtained by reacting these compounds with an active hydrogen group-containing compound or a polyol having a molecular weight of 200 or more, or an isocyanate modified product obtained by a reaction of these compounds (for example, a carbodiimidization reaction) is also included. Also, methanol, n
And polyisocyanates partially or wholly stabilized with a blocking agent having one active hydrogen in the molecule, such as butanol, benzyl alcohol, ethyl acetoacetate, ε-caprolactam, methyl ethyl ketone oxime, phenol and cresol.

As the foaming agent and foam stabilizer of the present invention, all the foaming agents and foam stabilizers used in ordinary urethane foaming can be used. Examples of the foaming agent include water,
Freon 11, Freon 12, Freon 22, Freon 141
b, methylene chloride. Examples of the foam stabilizer include SH-1 made by Toray Dow Corning Silicone.
93, Shin-Etsu Chemical F-341, Nippon Unicar L-
5420 and the like. The foam stabilizer is preferably used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the liquefied lignocellulosic material.

The method for producing the polyurethane foam of the present invention comprises:
The method is basically a method in which a mixture of a reaction liquid containing a liquefied lignocellulosic material and a compound containing a tertiary amine structure, to which a foaming agent and a foam stabilizer are added (hereinafter referred to as a polyol premix) and polyisocyanate are mixed. The polyol premix and polyisocyanate are preferably mixed in an amount of 30 to 200 mol of active hydrogen groups in the polyol premix with respect to 100 mol of NCO groups in the polyisocyanate. More preferably, the active hydrogen group is 70 to 150 mol per 100 mol of the NCO group.

To control the foaming rate, a polyurethane foaming catalyst can be added. As such a catalyst, all the catalysts normally used for polyurethane foaming can be used. For example, TEDA and TO manufactured by Tosoh
Examples include YOCAT-NP, Kao Kaiser No. 1 and Kao Kaiser No. 14 manufactured by Kao. In order to adjust the viscosity of the polyol premix, a plasticizer or the like can be added. For example, dioctyl phthalate, tricresyl phosphate, propylene carbonate, ethylene carbonate and the like are used.

As a device for obtaining the polyurethane foam of the present invention, any device used for ordinary polyurethane foaming can be used. The conditions for foaming, such as the raw material temperature, the mold temperature, and the stirring speed, can be the same as those used for ordinary polyurethane foaming.

In the polyurethane foam obtained by the present invention, other substances such as an antioxidant, an ultraviolet absorber, a heat resistance improver, a flame retardant, a coloring agent, an inorganic and an organic filler may be added as necessary during foaming. A plasticizer, a lubricant, an antistatic agent, a reinforcing material and the like can be added.

[0017]

Industrial Applicability According to the present invention, when producing a polyurethane foam, it is possible to expand the range of foaming conditions such as pH, and further improve the uniformity of the cell structure of the foam and the expansion ratio. It is possible to obtain a polyurethane foam which is excellent in its reproducibility of production and has few foam defects. As a result, the use of the lignocellulosic material, which is a part of effective utilization of wood resources, is extremely effective. Among the polyurethane foams, those exhibiting biodegradability are also recognized, but since the present invention contains a biodegradable substance called a lignocellulosic substance as one of its constituent main components, its properties are promoted. become. The polyurethane foam obtained in the present invention has a uniform cell structure, various heat insulating materials, synthetic wood, cushioning materials, cushioning materials,
It is effectively used for various sealing materials.

[0018]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In Examples and Comparative Examples,
All "%" mean "% by weight".

Example 1 40 g of dried cedar wood flour was preliminarily mixed with 3.6 g of 98% concentrated sulfuric acid and polyether polyol G-300 (average molecular weight: 30).
0, manufactured by Asahi Denka Co., Ltd.), and put in a 500 ml glass flask equipped with a reflux condenser together with 120 g of the mixed solution.
A liquefied lignocellulosic material was obtained by stirring and reacting in an oil bath at 50 ° C. for 1 hour. The hydroxyl value of the obtained liquefied lignocellulosic material was measured and found to be 310 g KOH / g. Then, 20 g of the solution cooled to room temperature is added to 20 g.
In a 0 ml beaker, 0.7 g of pyridine as a compound containing a tertiary amine structure was added and sufficiently stirred. SH-193 (Toray Dow Corning Silicone) 0.2g as foam stabilizer, Kaolizer No.1 (Kao) as catalyst
0.3 g of water and 1 g of water as a foaming agent were added and mixed with stirring, and then as a polyisocyanate, Millionate MR1
32 g of 00 (NCO content 31.0%, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added and stirred at 7,000 rpm for 10 seconds to give 10
A foam was obtained by pouring into a 00 ml cup. The obtained foam had a homogeneous cell and a specific gravity of 0.038 g / cm ³ , and no void was generated.

Example 2 21 g of a foaming raw material mixed and stirred in the same manner as in Example 1 was filled in a 100 × 100 × 50 mm aluminum box mold. The foam is a homogeneous cell with a specific gravity of 0.042 g / c
m ³ and no void was generated as in Example 1. No deformation was observed in the foam that was left at -20 ° C for 2 days.

Example 3 When a liquefied lignocellulosic material was obtained by the same production method as in Example 1, 20 g of pyridine as a compound containing a tertiary amine structure was added to the reaction mixture at room temperature after completion of the reaction, and the mixture was thoroughly stirred and heated to 110 ° C. What was evaporated for 30 minutes at × 10 mmHg was cooled to room temperature to obtain a lignocellulosic material. SH-193 (manufactured by Toray Dow Corning Silicone) 0.2g as a foam stabilizer and TEDA L as a catalyst were added to 20 g of the solution.
-33 (manufactured by Tosoh Corporation) 0.4 g, water as a foaming agent 1.0 g
After adding each and mixing and stirring, Millionate MR20
0 (NCO content 31.0%, made by Nippon Polyurethane Industry)
32g and stirred at 7,000 rpm for 10 seconds,
A foam was obtained by pouring into a 0 ml cup. This foam was a homogeneous cell, had a specific gravity of 0.039 g / cm ³ , and had no generation of voids.

Example 4 Liquefied and mixed and stirred in the same manner as in Example 2
1.5 g was filled in the same mold as in Example 2. The foam was a homogeneous cell and had a specific gravity of 0.043 g / cm ³ , and similarly, no void was generated.

Example 5 20 g of the same liquefied lignocellulosic material as in Example 1 except that dried mackerel wood flour was used, and 2-ethylpyridine 1.
1 g was added and the same millionion MR100 as in Example 1 was added.
A foam was obtained in the same manner as in Example 1 except that the amount was changed to 42 g. This foam is a homogeneous cell with a specific gravity of 0.039 g /
It was cm ³ , and no void was generated.

Example 6 48 g of 20 g of the same liquefied lignocellulosic material as in Example 1
% Sodium hydroxide solution 0.4 g, pyridine 0.4 g as a compound containing a tertiary amine structure, and well stirred, and Kaolizer No. 1 (manufactured by Kao) 0.2 g as a catalyst,
0.2 g of F-341 (produced by Shin-Etsu Chemical Co., Ltd.) as a foam stabilizer and 0.8 g of water as a foaming agent were added and mixed and stirred, and then 33 g of Millionate MR300 (NCO content 30.8%, made by Nippon Polyurethane Industry Co., Ltd.) was added and 7,000 rpm. In 10
It was stirred for 2 seconds and poured into a 1000 ml cup to obtain a foam. This foam is a homogeneous cell with a specific gravity of 0.037 g / cm
³ , there was no occurrence of voids.

Example 7 In 20 g of the same liquefied lignocellulosic material as in Example 1, 1.2 g of pyrimidine as a compound containing a tertiary amine structure
Was added and thoroughly stirred, and after adding 0.1 g of TEDA L-33 (manufactured by Tosoh Corp.) as a catalyst, 0.2 g of SH-193 (manufactured by Toray Dow Corning Silicone) as a foam stabilizer and 1 g of water as a foaming agent, and mixing and stirring. , Millionate MR
32 g of 100 (NCO content 31.0%, made by Nippon Polyurethane Industry Co., Ltd.) was added and stirred at 7,000 rpm for 10 seconds, and 1
A foam was obtained by pouring into a 000 ml cup. This foam was a homogeneous cell, had a specific gravity of 0.041 g / cm ³ , and did not generate voids.

Example 8 In the same manner as in Example 1, except that 20 g of the liquefied lignocellulosic material was added with 2.0 g of pyridine as a compound containing a tertiary amine structure and the pH was adjusted to 8.0, the method and methods of Example 1 were all repeated. To obtain a foam. This foam was a homogeneous cell and had a specific gravity of 0.037 g / cm ³ .

Example 9 The same method as in Example 1 except that 0.3 g of pyridine as a compound containing a tertiary amine structure was added to 20 g of the same liquefied lignocellulosic material as in Example 1 to bring the pH to 4.3. To obtain a foam. This foam was a homogeneous cell and had a specific gravity of 0.043 g / cm ³ .

Comparative Example 1 48 g of 20 g of the same liquefied lignocellulosic material as in Example 1
% Sodium hydroxide solution (0.9 g) and stirred well,
SH-193 (manufactured by Toray Dow Corning Silicone Co., Ltd.) as a foam stabilizer and 0.6 g of water as a foaming agent were respectively added and mixed and stirred, and then Millionate MR100 (NCO
36 g of 31.0% content, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added, stirred at 7,000 rpm for 10 seconds, and poured into a 1000 ml cup to obtain a foam. This foam was a non-homogeneous cell, had a specific gravity of 0.049 g / cm ³ , and generation of voids was observed.

Comparative Example 2 Polyurethane foam obtained by the same method as in Comparative Example 1 except that the amount of 48% sodium hydroxide solution used was 0.4 g and the amount of water used was 1 g. The body had a fairly severe contraction.

Comparative Example 3 The product obtained by the same method as in Comparative Example 1 except that the amount of the 48% sodium hydroxide solution used was changed to 1.8 g in the method of Comparative Example 1 and water was not used, It did not become a good foam.

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Claims (3)

[Claims] 1. A reaction liquid containing a liquefied lignocellulosic substance obtained by reacting a lignocellulosic substance and a polyhydric alcohol in the presence of an acid catalyst is treated with an alkali metal hydroxide and / or an alkaline earth metal hydroxide. A method for producing a polyurethane foam, which comprises neutralizing with a compound containing a tertiary amine structure, which may contain, and then reacting with a polyisocyanate in the presence of a foaming agent. 2. A reaction solution containing a liquefied lignocellulosic material obtained by reacting a lignocellulosic material with a polyhydric alcohol in the presence of an acid catalyst is treated with an active hydrogen group-containing compound, an alkali metal hydroxide and / or an alkali. A method for producing a polyurethane foam, which comprises neutralizing with a compound containing a tertiary amine structure, which may contain an earth metal hydroxide, and then reacting with a polyisocyanate in the presence of a foaming agent. 3. A reaction solution containing a liquefied lignocellulosic material obtained by reacting a lignocellulosic material and a polyhydric alcohol in the presence of an acid catalyst, is treated with an alkali metal hydroxide and / or an alkaline earth metal hydroxide. Of a polyurethane foam, characterized in that it is neutralized with a compound containing a tertiary amine structure, which may contain an active hydrogen group-containing compound, and then reacted with a polyisocyanate in the presence of a blowing agent. Manufacturing method.