JPH08198920A - Polymer-dispersed polyol and its production - Google Patents

Abstract

PURPOSE: To obtain a polymer-dispersed polyol capable of providing a polyurethane foam improved in performances such as impact resilience, vibration characteristics and moldability by carrying out the polymerization in a polyoxyalkylene polyol prepared by conducting the ring opening addition polymerization using a cesium-based catalyst. CONSTITUTION: (B) A monomer having a polymerizable unsaturated group (e.g. acrylonitrile alone) is polymerized in (A) a polyoxyalkylene polyol prepared by carrying out the ring opening addition polymerization of (iii) an alkylene oxide (e.g. ethylene oxide) using (i) an initiator containing an active hydrogen group and (ii) a cesium-based catalyst, preferably cesium hydroxide. The polymer concentration is preferably 2-60wt.%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polymer-dispersed polyol and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, various new studies have been made to improve the properties of polyurethane elastic foams. For example, in order to improve the riding comfort of seat cushions as automobiles become more sophisticated, impact resilience,
Improvements in durability and vibration characteristics are desired. Regarding the vibration characteristics, the relationship between body vibration and human beings is not uniform, but a frequency range in which humans are particularly sensitive (for example, 4 to 8 Hz, or 6 to
It is proposed that a particularly large attenuation of 20 Hz) is effective for improving the riding comfort.

In order to improve these properties, a compound or mixture called a polymer-dispersed polyol obtained by polymerizing a high molecular weight polyoxyalkylene polyol or a monomer having a polymerizable unsaturated group in a high molecular weight polyoxyalkylene polyol is used. It has been considered effective to use them to make seat cushions.

Generally, a polyoxyalkylene polyol used as a raw material for polyurethane is used as an initiator containing an active hydrogen group such as a polyhydric alcohol by using a sodium or potassium catalyst such as sodium hydroxide or potassium hydroxide. It is produced by ring-opening addition polymerization of alkylene oxide such as propylene oxide.

In this production method, a monool having an unsaturated group is produced as a by-product, and the amount of the unsaturated monool produced increases as the molecular weight of the polyol increases (the hydroxyl value decreases). Molecular weight between cross-linking points (terminal OH) widely used as a raw material for polyurethane elastic foam
In a polyoxyalkylene polyol having a molecular weight per group of about 1000, the presence of this unsaturated monool was not a problematic amount.

However, in the high molecular weight (low hydroxyl value) polyoxyalkylene polyol used as a raw material for the high-elasticity polyurethane foam, the presence of the unsaturated monool may cause a problem. For example, the molecular weight between cross-linking points is 1
With a polyoxyalkylene polyol of about 600, the total degree of unsaturation is usually 0.07 meq / g or more.

Even if an elastic foam is produced by using a polyoxyalkylene polyol having a high degree of total unsaturation, problems such as a decrease in hardness, a decrease in impact resilience, a deterioration in compression set, and a decrease in cure property during foam molding are caused. Occurs. Furthermore, even if an attempt is made to produce a polyoxyalkylene polyol having a low hydroxyl value using a sodium-based or potassium-based catalyst,
The total degree of unsaturation became extremely high, and it was virtually impossible to produce a polyol having a molecular weight between crosslinking points (molecular weight per terminal OH group) of more than 2000. Therefore, there is a limit to improving the riding comfort performance of automobile seats, cushions, and the like.

Polymer-dispersed polyols are roughly classified into two types, one is a polymer-dispersed polyol obtained by polymerizing a monomer in a substantially saturated polyol having no polymerizable unsaturated group, and the other is a polymerized polyol. It is a polymer-dispersed polyol obtained by copolymerizing a monomer with a polyunsaturated group-containing polyol. Regarding the polymer-dispersed polyol obtained by polymerizing a monomer in a substantially saturated polyol having no polymerizable unsaturated group, it is said that a part of the polymer is grafted to the polyol compound.

Various polyoxyalkylene polyols and polyester polyols are known as polyols, and a typical polyol is polyoxyalkylene polyol.

[0010]

Polymer-dispersed polyols are used to improve the mechanical properties of polyurethane. In particular, a flexible urethane foam promotes cell communication and improves foam hardness. Further, the urethane elastomer can increase the hardness of the resin and increase the elastic modulus.

However, while such properties can be improved, the polymer particles dispersed in the polyoxyalkylene polyol act as a foreign substance in the molded polyurethane and deteriorate in various physical properties such as elongation, impact resilience, and deterioration of tear strength. Is known to cause. These problems can be expected to be solved by a polymer-dispersed polyol using a polyoxyalkylene polyol having a high molecular weight and a low total unsaturation degree, but as described above, the conventional sodium-based and potassium-based catalysts have There was a limit to the reduction of unsaturation.

[0012]

The present invention is the following invention which has been made to solve the above-mentioned problems.

Characterized by polymerizing a monomer having a polymerizable unsaturated group in a polyoxyalkylene polyol obtained by subjecting an alkylene oxide to ring-opening addition polymerization using a cesium-based catalyst as an initiator containing an active hydrogen group. And a method for producing a polymer-dispersed polyol.

A method for producing a polyurethane, which comprises reacting a polymer-dispersed polyol produced by the production method with a polyisocyanate compound.

A polyoxyalkylene polyol obtained by subjecting an alkylene oxide to ring-opening addition polymerization using a cesium-based catalyst as an initiator containing an active hydrogen group, and polymer fine particles stably dispersed in the polyol are prepared. A polymer dispersed polyol containing.

Examples of the cesium-based catalyst used in the present invention include metal cesium, cesium methoxide,
Examples thereof include cesium alkoxides such as cesium ethoxide and cesium propoxide, cesium hydroxide, and cesium carbonate. Cesium hydroxide is preferred.

The amount of the cesium-based catalyst used is preferably 0.05 to 1.5% by weight, and particularly preferably 0.1 to 1.0% by weight in the finished polyol as cesium. If it is less than 0.05% by weight, the reaction rate is not sufficient,
If it exceeds 1.5% by weight, the production cost of the polyol increases, which is not preferable.

However, as a part of the polyol, a polyoxyalkylene polyol or polytetraalkylene obtained by ring-opening addition polymerization of alkylene oxide using a sodium-based or potassium-based catalyst represented by sodium hydroxide or potassium hydroxide is used. Methylene glycol, polyester-based polyols, polyester-ether polyols, polycarbonate-based polyols, hydroxyl group-containing polydiene-based polymers and the like can also be used.

In the present invention, the active hydrogen compound that can be used as the initiator is a compound having an active hydrogen-containing functional group such as a hydroxyl group, an amino group, a mercapto group and a carboxyl group to which an alkylene oxide can be added. As the polyoxyalkylene polyol useful as a polyurethane raw material, a polyvalent hydroxyl group-containing compound, that is, a polyhydroxy compound or an amino group-containing compound is usually used.

Typical examples of polyhydroxy compounds are polyhydric alcohols, polyhydric phenols, and polyethers having a lower molecular weight than the target polyol obtained by adding cyclic ethers such as alkylene oxide to these hydroxy compounds and other initiators. It is a polyol. Compounds having a hydroxyl group such as other polyester polyols may also be used.

Preferred polyhydroxy compounds are polyols such as polyhydric alcohols and polyhydric phenols, and polyether polyols obtained by adding cyclic ethers to these polyols. These polyhydroxy compounds may also be a mixture of two or more. Specific examples of polyhydroxy compounds include, but are not limited to, the following and their cyclic ether adducts. Water is a kind of divalent polyhydroxy compound. The molecular weight of the cyclic ether adduct is not particularly limited, but is preferably 1/2 or less, and particularly preferably 1/5 or less of the molecular weight of the intended polyol compound.

Polyhydric alcohol; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, water, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, 1,6-hexanediol, Glycerin trimethylolpropane, pentaerythritol, diglycerin, sorbitol, dextrose, methyl glucoside, sucrose.

Polyhydric phenol; bisphenol A, phenol-formaldehyde initial condensation product.

Amino compounds: piperazine, aniline, monoethanolamine, diethanolamine, triethanolamine, ammonia, aminoethylpiperazine, ethylenediamine, toluylenediamine, diethylenetriamine and their cyclic ether adducts.

The cyclic ether used in the present invention includes
A compound containing a 3- to 4-membered cyclic ether group having one oxygen atom in the ring is suitable, and a compound having one 3-membered cyclic ether group (monoepoxide) is preferable.
A particularly preferred compound is an alkylene oxide having 2 to 4 carbon atoms. In addition, styrene oxide, glycidyl ether, and other monoepoxides may be used.

Preferred alkylene oxides are ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether.

Two or more of these cyclic ethers can be used in combination. In that case, they can be mixed and reacted, or they can be reacted sequentially. A particularly preferred cyclic ether is an alkylene oxide having 2 to 4 carbon atoms, particularly propylene oxide, or a combination of propylene oxide and ethylene oxide.

There are two methods for producing a polymer-dispersed polyol using such a polyol. One method is a method in which a polymerizable unsaturated monomer is polymerized in a polyol to directly deposit particles, and the other method is to deposit particles in a solvent in the presence of a grafting agent that stabilizes the particles,
In this method, the polyol and the solvent are replaced to obtain a stable dispersion. In the present invention, either method can be adopted, and the former method of polymerizing in a polyol is particularly preferable.

As the monomer having a polymerizable unsaturated group, a monomer having one polymerizable double bond is usually used, but the monomer is not limited thereto. As specific monomers, acrylonitrile, styrene, acrylamide, acrylic acid ester, methacrylic acid ester, vinyl acetate and the like are preferable. For example, α-methylstyrene, dimethylstyrene, styrene derivatives such as halogenated styrene, butadiene, diene-based monomers such as isoprene,
Acrylic derivatives such as methacrylonitrile, butyl acrylate and benzyl methacrylate, vinyl halides such as vinyl chloride, unsaturated fatty acid esters such as maleic acid diester and itaconic acid diester, and other monomers can also be used.

These monomers can be used alone or in combination with other monomers to form a copolymer. The most preferred monomers are acrylonitrile alone, styrene alone, acrylonitrile and styrene, or a combination of acrylonitrile or other monomers based on styrene.

As the polymerization initiator, a polymerization initiator of the type that produces free radicals to initiate polymerization is usually used.
Specifically, for example, azobisisobutyronitrile, azobismethylbutyronitrile, benzoyl peroxide,
Examples include diisopropyl peroxydicarbonate, acetyl peroxide, di-t-butyl peroxide, dicumyl peroxide, lauroyl peroxide and persulfate. Particularly preferred are azo-based polymerization initiators such as azobisisobutyronitrile and azobismethylbutyronitrile.

The polymerization reaction is carried out at a temperature not lower than the decomposition temperature of the polymerization initiator, usually at 80 to 160 ° C. The amount of monomer used is
About 60% by weight or less, particularly 10 to 50% by weight, based on the total amount of all polyols and monomers, is preferred. After completion of the polymerization reaction, the obtained polymer or polyol can be used as it is as a raw material for polyurethane, but it may be subjected to post-treatment such as removal of impurities such as decomposition products of a polymerization initiator.

Although a polyol composition in which polymer particles are stably dispersed can be obtained by the above-mentioned production method, it may be difficult to obtain a stable dispersion depending on the monomer used. Further, in order to improve the dispersion stability of the particles, a stabilizer or a grafting agent having a double bond in the molecule can be used.

As the grafting agent, a high molecular weight polyol or monool obtained by reacting an active hydrogen compound having a vinyl group, an allyl group, an isopropyl group or the like with an alkylene oxide as an initiator, a maleic anhydride or an anhydride. Obtained by reacting an unsaturated carboxylic acid such as itaconic acid, maleic acid, fumaric acid, acrylic acid and methacrylic acid or an acid anhydride thereof, and then adding alkylene oxide such as propylene oxide and ethylene oxide if necessary. Examples thereof include high molecular weight polyols or monools, reaction products of polyols with polyisocyanates and unsaturated alcohols such as 2-hydroxyethyl acrylate and butenediol, and reaction products of polyols with unsaturated epoxy compounds such as allyl glycidyl ether.

It is desirable that these compounds have a hydroxyl group as a particle stabilizer or a grafting agent, but a compound having no hydroxyl group also sufficiently contributes as a particle stabilizer.

The amount of the polymer fine particles in the polymer-dispersed polyol is not particularly limited, and is 60% by weight or less, particularly 50
It is preferably not more than wt%. The lower limit of the amount is 2% by weight, preferably 5% by weight, more preferably 10% by weight. When the polymer-dispersed polyol is used as a raw material for polyurethane, it can be diluted with the above-mentioned polyol and used. The lower limit of the amount of polymer particles in the polymer-dispersed polyol mixture after dilution is preferably the lower limit amount in the above-mentioned polymer-dispersed polyol.

The present invention is also a method for producing a polyurethane by reacting the polymer-dispersed polyol of the present invention with a polyisocyanate compound. As polyurethane, flexible polyurethane foam and polyurethane elastomer are preferable. Polyurethane is produced by a one-shot method produced by mixing a polyol component and a component containing a polyisocyanate compound, a prepolymer method via a prepolymer, or the like.

The polyol component comprising the polymer-dispersed polyol of the present invention alone or a mixture of polyols containing the same may further include a catalyst, a foam stabilizer, a foaming agent, a filler, a cross-linking agent, a chain extender, a stabilizer, a colorant and the like. You may add the additive of. In general polyurethane foam production, a catalyst, a foaming agent, and a foam stabilizer are often essential components.

Suitable catalysts are amine-based catalysts such as tertiary amines and organometallic compounds such as organotin compounds. As a foaming agent, water or difluorodichloromethane,
1,1-dichloro-1-fluoroethane, 1-chloro-
1,1-difluoroethane, 1,1-dichloro-2,
2,2-trifluoroethane, methylene chloride and other halogenated hydrocarbons are suitable. As the foam stabilizer, an organosilicon compound-based surfactant is suitable.

Examples of the chain extender include polyhydric alcohols, alkanolamines, polyamines, and polyhydric alcohols, alkanolamines, sugars, polyamines, monoamines, polyhydric phenols, and the like which are obtained by adding a small amount of alkylene oxide. There are polyether polyols of molecular weight. Furthermore, low molecular weight polyester polyols and the like can also be used. Preferably, polyhydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol and glycerin, alkanolamines such as diethanolamine and triethanolamine, and polyether polyols having a hydroxyl value of 200 or more are used.

The polyisocyanate compound is an aromatic, alicyclic or aliphatic polyisocyanate having two or more isocyanate groups, a mixture of two or more kinds thereof, and a modified polyisocyanate obtained by modifying them. There is. Specifically, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate (common name:
Examples include polyisocyanates such as crude MDI), xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, and their prepolymer modified products, nurate modified products, urea modified products, and carbodiimide modified products.

The characteristic feature of the polymer-dispersed polyol of the present invention is that the improvement in the mechanical properties of the polyurethane using the same is remarkable as compared with the conventional polymer-dispersed polyol.

In particular, the polyurethane foam using the polymer-dispersed polyol of the present invention has improved foam hardness and strength, but the foams using the conventional polymer-dispersed polyol have deteriorated impact resilience, elongation, tear strength and compression set. It has a feature that distortion and vibration characteristics are improved at the same time.

Although the mechanism of action for improving the characteristics as described above is still unclear, alkylene oxides such as propylene oxide and ethylene oxide are used as an initiator such as polyhydric alcohol by using a conventional sodium-based or potassium-based catalyst. Compared with the polyoxyalkylene polyol obtained by ring-opening addition-polymerization of polyoxyalkylene polyol, the content of monool produced as a by-product is reduced in the polyoxyalkylene polyol obtained by ring-opening addition polymerization using a cesium-based catalyst. It is presumed that this is reflected in the case of using it in the polymer-dispersed polyol, and the effect of improving the characteristics was imparted.

[0045]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Parts indicate parts by weight.

The following polyols A to C are used as the polyol.
It was used.

Polyol A: Hydroxyl value of 28, obtained by ring-opening addition polymerization of propylene oxide and ethylene oxide with glycerin in this order using cesium hydroxide as a catalyst.
Oxyethylene group content 15% by weight, total degree of unsaturation 0.0
31 meq / g of polyoxyalkylene triol.

Polyol B: Hydroxyl value of 28, obtained by ring-opening addition polymerization of propylene oxide and ethylene oxide on glycerin in this order using potassium hydroxide as a catalyst.
Oxyethylene group content 15% by weight, total degree of unsaturation 0.0
75 meq / g polyoxyalkylene triol.

Polyol C: Hydroxyl value 28, oxyethylene group content 13% by weight, total unsaturation degree 0 obtained by ring-opening addition polymerization of propylene oxide and ethylene oxide in this order with pentaerythritol using potassium hydroxide as a catalyst. 0.074 meq / g of polyoxyalkylene tetraol.

[Example 1] 66 in a 5 liter pressure reaction tank
12 parts of polyol A, acrylonitrile (in the table, A
N) 11 parts, styrene (St in the table) 11 parts, and azobisisobutyronitrile 0.5 parts while stirring the mixture 2
I put in it over time. Then, stirring was continued at the same temperature for about 0.5 hours. After the reaction was completed, unreacted monomers were removed by degassing under reduced pressure at 110 ° C. for 2 hours to obtain a pale yellow polymer-dispersed polyol (POP-A).

Example 2 A mixture of 79 parts of polyol A, 21 parts of acrylonitrile, and 0.5 part of azobisisobutyronitrile was continuously fed to a continuous reaction tank kept at a temperature of 125 ° C. The polymer-dispersed polyol was continuously extracted from the reaction vessel to synthesize it. After the reaction,
Unreacted monomer was removed by degassing under reduced pressure at 110 ° C. for 2 hours to obtain a yellow polymer-dispersed polyol (POP-A ′).

[Comparative Example 1] 66 in a 5 liter pressure reactor.
10 parts of polyol B was stirred and charged, and a mixture of 12 parts of polyol A, 11 parts of acrylonitrile, 11 parts of styrene and 0.5 part of azobisisobutyronitrile was added over 2 hours while stirring at 110 ° C. . Then, stirring was continued at the same temperature for about 0.5 hours. After the reaction was completed, unreacted monomers were removed by degassing under reduced pressure at 110 ° C. for 2 hours to obtain a pale yellow polymer-dispersed polyol (POP-B).

[Comparative Example 2] A mixture of 79 parts of polyol A, 21 parts of acrylonitrile, and 0.5 part of azobisisobutyronitrile was continuously supplied to a continuous reaction tank maintained at a temperature of 125 ° C. The polymer-dispersed polyol was continuously extracted from the reaction vessel to synthesize it. After the reaction,
Unreacted monomer was removed by degassing under reduced pressure at 110 ° C. for 2 hours to obtain a yellow polymer-dispersed polyol (POP-B ′).

Table 1 shows the polymer composition, the polymer concentration, the viscosity at 25 ° C., and the hydroxyl value of the polymer-dispersed polyol obtained in the above example.

Highly elastic polyurethane foams were prepared using the polymer-dispersed polyols. Of the raw materials, a polyisocyanate compound (a mixture of 2,4-MDI, polymeric MDI, TDI-80, and an isocyanate group content of 27.0% by weight) was placed in one raw material tank of a reaction injection molding apparatus (high pressure foaming machine). , The liquid temperature is 25 to 3
Adjusted to 0 ° C.

Further, the polyol and the foam stabilizer shown in Table 2 (SRX-274C, manufactured by Toray Silicon Co., Ltd.) 1.0
Part, amine catalyst α (manufactured by Tosoh Corporation, TEDA L-3)
3) 0.35 parts, amine catalyst β (TOSOH CORPORATION, TO
A mixture of 0.05 parts of YOCAT-ET) and 1.0 part of water was placed in the other raw material tank of the reaction injection molding apparatus, and the liquid temperature was adjusted to 25 to 30 ° C.

Both have an isocyanate index of 10
The mixture was mixed and injected at a ratio of 0. The isocyanate index means 100 times the equivalent of the isocyanate compound to 1 equivalent of all the active hydrogen compounds. The injection conditions were an injection pressure of 140 kg / cm ^{2 and an} injection amount of 300 g / sec. The mold has 400 mm x 400 mm x 100 m
A mold having an inner dimension of m (t) is used, and the mold temperature is 58
Adjusted to ~ 62 ° C. Demolding from the mold is 4 after material injection.
Went in minutes.

Table 2 shows the physical properties of the obtained high-elasticity polyurethane foam.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

As is clear from Table 2, a polymerizable unsaturated group-containing monomer is polymerized in a polyoxyalkylene polyol obtained by subjecting an alkylene oxide to ring-opening addition polymerization using a cesium-based catalyst. The polymer-dispersed polyol produced as described above has improved properties such as impact resilience, vibration characteristics, and moldability when a polyurethane foam is produced by using the polymer-dispersed polyol, as compared with the case where a conventionally known polymer-dispersed polyol is used.

Claims (5)

[Claims] 1. Polymerizing a monomer having a polymerizable unsaturated group in a polyoxyalkylene polyol obtained by ring-opening addition polymerization of an alkylene oxide using a cesium-based catalyst as an initiator containing an active hydrogen group. A method for producing a polymer-dispersed polyol, comprising: 2. The method according to claim 1, wherein the cesium-based catalyst contains cesium hydroxide as a main component. 3. The method according to claim 1, wherein the polymer concentration of the polymer-dispersed polyol is 2 to 60% by weight. 4. A method for producing a polyurethane, which comprises reacting a polymer-dispersed polyol produced by the method according to any one of claims 1 to 3 with a polyisocyanate compound. 5. Polyoxyalkylene polyol obtained by subjecting alkylene oxide to ring-opening addition polymerization using a cesium-based catalyst as an initiator containing an active hydrogen group, and polymer fine particles stably dispersed in the polyol. A polymer-dispersed polyol containing and.