JP2623221B2 - Method for producing thermoplastic urethane resin dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic urethane resin dispersion. For more information,
The present invention relates to a method for producing a thermoplastic urethane resin dispersion capable of obtaining a powder useful for a molding material and the like in addition to slush molding and powder coating excellent in heat melting property, flexibility and durability.

[0002]

2. Description of the Related Art In recent years, the slush molding method has been used in automobile interiors because products having complicated shapes (undercut, deep drawing, etc.) can be easily molded, the thickness can be made uniform, and the yield rate of materials is good. It is widely used mainly for materials and the like, and soft polyvinyl chloride (hereinafter referred to as PVC) powder is mainly used for such purposes. However, since the softened PVC contains a large amount of a low-molecular plasticizer, an oil film is formed (fogged) on a windshield or the like of a vehicle due to volatilization of the plasticizer during long-term use, and the visibility of the driver is increased. Of the matting effect and loss of the soft feeling due to the transfer of the plasticizer to the surface of the molded product, and further, yellowing due to the deterioration of PVC over time.
Further, as a material giving a soft feeling without using a low-molecular plasticizer, a material obtained by modifying a PVC by blending a flexible thermoplastic polyurethane resin is known (for example, Japanese Patent Publication No. 53-29705, Japanese Patent Publication No. 59-39464, JP-B-60-30688). However, in any case, since the main resin is PVC, the problem of the deterioration with time of the molded product has not been solved yet. In order to solve the above-mentioned problems, attempts have recently been made to obtain desired physical properties using only a polyurethane resin (for example, Japanese Patent Application Laid-Open No. 2-38453). Costly and environmentally problematic. In order to solve such a problem, a method of producing a urethane resin powder in water has also been proposed (Japanese Patent Laid-Open No. 3-97712). In this method, use of a chain extender such as polyamine is described, but it is difficult for such a chain extender to reach the inside of the particle, so that unreacted substances remain inside the particle. Was. In addition, in this method, a reaction between the isocyanate group and water of the dispersion medium occurs, and a polyurethane resin having a high molecular weight is easily formed. Therefore, the resin powder produced by this method hardly melts during molding, and as a result, Not useful for slush molding.

[0003]

DISCLOSURE OF THE INVENTION The present invention is directed to a thermoplastic urethane resin dispersion capable of obtaining a thermoplastic urethane resin powder having improved heat melting property, flexibility and durability, which has improved the above-mentioned problems. It is intended to provide a method for producing a body.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a thermoplastic urethane resin dispersion excellent in heat melting property, flexibility and durability and capable of realizing low cost. The present inventors have found a method for producing a body and have reached the present invention. That is, the present invention provides a urethane resin (B) having an isocyanate group in the presence of water and a dispersion stabilizer (A).
And a blocked chain extender (C). A method for producing a thermoplastic urethane resin dispersion.

The dispersion stabilizer (A) used in the present invention has a function as a protective colloid, and may be water-insoluble or water-soluble, but is preferably substantially water-insoluble. More preferred are substantially non-emulsifiable ones among the water-insoluble dispersants in view of the dispersion particle diameter in the thermoplastic urethane resin dispersion.

[0006] The water-insoluble dispersion stabilizer comprises a portion (A1) having an affinity for the urethane resin (B) and a portion (A2) having a hydrophilic property.
The bonding form of 2) is not particularly limited, but an ester bond,
A urethane bond is preferable, and a urethane bond is particularly preferable. For example, a dispersion stabilizer can be prepared by mixing and heating a compound constituting (A1), a compound constituting (A2) and a diisocyanate or a dicarboxylic anhydride while stirring.

The compound constituting (A1) preferably has the same or similar structure as the polyol used for the urethane resin (B), and its number average molecular weight is usually 50.
0 to 10,000.

As the compound constituting (A1), those having a solubility parameter (hereinafter abbreviated as SP value) of usually 8 to 12 can be used, and the SP value difference from the polyol (B2) described later used in the urethane resin (B) can be used. Is preferably 0.5 or less. (The calculation method of the SP value is Polymer Engineering.
eering and Science, Feburu
ary, 1974, Vol. 14, No. 2 P. 14
If the SP value and the molecular weight are outside the above ranges, dispersion of (B) in water becomes difficult.

Examples of the compound constituting (A1) include a polyol compound having an ester group, an oxyalkylene group (having two or more carbon atoms), an unsaturated hydrocarbon group, and the like. Examples thereof include polyester polyol, polycaprolactone polyol, polycarbonate polyol and the like. Examples of those having an oxyalkylene group include polyethylene polyols and polypropylene polyols. Examples of those having an unsaturated hydrocarbon group include polybutadiene polyol. Of these, those having an ester group are preferred. In the polyol, those having 2 hydroxyl groups are preferred, but those having more than 2 hydroxyl groups can be used as long as they are 20% by weight or less based on the compound constituting (A1).

The polyester polyols include those obtained by condensation polymerization of a low molecular weight polyol and a polycarboxylic acid and those obtained by ring-opening polymerization of lactone.

The low molecular polyol includes, for example, aliphatic low molecular diols [ethylene glycol, diethylene glycol, propylene glycol and the like]; low molecular diols having a cyclic group [eg m- or p-xylylene glycol, bisphenol A] Alkylene oxide adducts and the like].

The polycarboxylic acids include, for example, aliphatic dicarboxylic acids (succinic acid, adipic acid, maleic acid, fumaric acid, etc.), aromatic dicarboxylic acids (terephthalic acid, isophthalic acid, etc.) and two or more of these. Combination is mentioned.

Examples of the lactone include γ-butyrolactone and ε-caprolactone.

As a specific example of the compound constituting (A1), polyethylene adipate polyol (SP value = 1)
0.9), polyethylene butylene adipate polyol (SP value = 10.7), polybutylene hexylene adipate polyol (SP value = 10.3), polydiethylene glycol isophthalate polyol (SP value = 10.
8) Polycondensate of terephthalic acid with PO2 mole adduct of bisphenol A (SP value = 10.1)
Polycondensate of PO2 mole adduct of fumaric acid with SP value = 1
0.1), poly ε-caprolactone polyol (SP value = 10.2), polypropylene polyol (SP value =
8.7), polytetramethylene polyol (SP value =
9.0), polyhexamethylene polycarbonate polyol (SP value = 9.8), polybutadiene polyol (SP value = 8.6) and the like.

As the compound constituting (A2), the oxyethylene unit is usually 30% by weight or more, preferably 50% by weight.
The number average molecular weight containing 500% by weight or more is usually 500 to 10,000.
0, preferably 1,000 to 6,000 polyoxyalkylene glycol. Specifically, polyethylene glycol, polyoxyethylene propylene glycol, polyethylene glycol PO (propylene oxide), EO (ethylene oxide) random adduct (P
The ratio of O and EO is 80/20 to 20/80 by weight.)
And the like. Of these, polyethylene glycol, polyethylene glycol PO, and EO random adduct are preferred.

The ratio of (A1) to (A2) is usually 20/80 to 80/20, preferably 30/70 to 7 by weight.
0/30. If the SP value of (A1), the ratio of (A1) and (A2) and the molecular weight are out of the above-mentioned ranges, the dispersibility of the urethane resin (B) in water is poor and a uniform dispersion cannot be obtained.

The group linking (A1) and (A2) is not particularly restricted but includes, for example, urethane groups and ester groups.

Examples of the case where (A1) and (A2) are bonded via a urethane group (a water-insoluble dispersion stabilizer) include (A)
A method in which 1), (A2) and the diisocyanate are heated while being mixed and stirred to prepare a dispersion stabilizer. As the diisocyanate, carbon number (N
2 to 12 aliphatic diisocyanates (excluding carbon in the CO group) [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate,
Alicyclic diisocyanate having 4 to 15 carbon atoms (excluding carbon in the NCO group) [isophorone diisocyanate, dicyclohexyl methane diisocyanate, cyclohexylene diisocyanate, methyl cyclohexylene diisocyanate, etc.] 8 to 12 carbon atoms (excluding carbon in the NCO group)
Aromatic / aliphatic diisocyanates [xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.]; aromatic diisocyanates [tolylene diisocyanate, diethylbenzene diisocyanate, diphenylmethane diisocyanate, naphthylene diisocyanate, etc.] and And / or a modified product thereof (a diisocyanate having a carbodiimide group, a uretdione group, a uretoimine group and / or a urea group); and a combination of two or more of these.

Examples of bonding (A1) and (A2) via an ester group (water-insoluble dispersion stabilizers) include, for example, (A1), (A2) and a dicarboxylic anhydride mixed with heating while stirring. By doing so, a method for preparing a dispersant can be exemplified. Specific examples of the dicarboxylic anhydride include:
Acid anhydrides of aliphatic dicarboxylic acids (succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, maleic acid, fumaric acid, etc.), and acid anhydrides of aromatic dicarboxylic acids (terephthalic acid, isophthalic acid, etc.) and these In combination of two or more.

The water-soluble dispersion stabilizer in (A) includes:
Methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, cellulose-based water-soluble resins such as carboxymethylcellulose, polyvinyl alcohol, polyacrylates, polyethylene glycol, polyvinylpyrrolidone, polyacrylamide, tertiary phosphates and the like. Alcohols are preferred.

The urethane resin (B) used in the present invention is a prepolymer having an isocyanate group concentration (hereinafter abbreviated as NCO%) of 1 to 50% by weight. Among them, preferred is NCO% 1 to 10% by weight.
The number average molecular weight of (B) is usually 500 to 100,000,
Preferably, those having 5000 to 30000 are used.

The polyisocyanate (B1) for producing the urethane resin (B) includes aliphatic polyisocyanates having 2 to 12 carbon atoms (excluding the carbon in the NCO group) [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene Diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate, 2,
6-diisocyanatomethylcaproate, etc.]; an alicyclic polyisocyanate having 4 to 15 carbon atoms (excluding carbons in the NCO group) [isophorone diisocyanate, dicyclohexylmethane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, etc.]; carbon 8 to 12 (excluding carbon in the NCO group) aromatic / aliphatic polyisocyanate [xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.]; Range isocyanate, diethylbenzene diisocyanate, diphenylmethane diisocyanate,
Naphthylene diisocyanate, etc.] and / or a modified product thereof (a diisocyanate having a carbodiimide group, a uretdione group, a uretoimine group and / or a urea group); and a combination of two or more of these.
The amount of the polyisocyanate having 3 or more functional groups is 30% by weight or less based on the diisocyanate. If necessary, the number of isocyanate groups may be 3 together with diisocyanate.
The above polyisocyanates can be used. The amount of the polyisocyanate used is 30% by weight or less based on the diisocyanate.

Of those exemplified as (B1), preferred are aliphatic diisocyanates and alicyclic diisocyanates, and particularly preferred are hexamethylene diisocyanate (hereinafter abbreviated as HDI) and isophorone diisocyanate (hereinafter abbreviated as IPDI). ) And dicyclohexylmethane diisocyanate (hereinafter, referred to as
Hydrogenated MDI).

The polyol (B2) for producing the urethane resin (B) includes polyether polyols, polyester polyols, silicone polyols, polybutadiene polyols, fluorine-containing polyols, polymer polyols, glycidyl group-containing polyols, and mixtures thereof. . Among these, preferred are polyester polyols, and particularly preferred are polyester diols having 2 hydroxyl groups. If necessary, a polyol having 3 or more hydroxyl groups can be used together with the polyester diol. The amount of the polyol used is 30% by weight or less based on the diol. (B2) has a number average molecular weight of usually 100 to 10,000, preferably 5
00 to 3000.

Examples of the polyether polyol include compounds having a structure in which an alkylene oxide is added to a compound having two or more active hydrogen atoms (eg, a polyhydric alcohol, a polyhydric phenol, etc.) and a mixture thereof. Of these, preferred are polyether polyols in which different alkylene oxides, for example, PO and EO are added in a block shape.

The polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-
Examples include alkylene glycols such as hexanediol and neopentyl glycol, and polyhydric alcohols such as diols having a cyclic group (for example, those described in Japanese Patent Publication No. 45-1474). Examples of the polyhydric phenol include monocyclic polyhydric phenols such as pyrogallol, hydroquinone, and phloroglucin; and bisphenols such as bisphenol A and bisphenol sulfone. Preferred among these are polyhydric alcohols.

Examples of the alkylene oxide include ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,3-, 1,4 or 2,3-butylene oxide, styrene oxide and the like. And combinations of two or more of these (block or random addition). Of these, EO and PO are preferably used in combination, and more preferably used in the form of block addition.

Examples of the polyester polyol include those obtained by condensation polymerization of a low-molecular-weight polyol and a polycarboxylic acid, those obtained by ring-opening polymerization of lactone, a mixture of two or more of these, and mixed modified products.

The low molecular polyol includes, for example, aliphatic low diols [ethylene glycol, diethylene glycol, propylene glycol, etc.]; diols having a cyclic group [for example, those described in JP-B-45-1474: 1,4 -Bis (hydroxymethyl) cyclohexane, m- or p-xylylene glycol, etc.] and a combination of two or more of these.

Specific examples of the polycarboxylic acid include aliphatic dicarboxylic acids (succinic acid, adipic acid, sebacic acid,
Examples thereof include glutaric acid, azelaic acid, maleic acid, and fumaric acid), aromatic dicarboxylic acids (such as terephthalic acid and isophthalic acid), and combinations of two or more of these.

Examples of the lactone include γ-butyrolactone and ε-caprolactone.

The blocked chain extender (C) used in the present invention refers to a compound (C1) having two or more active hydrogen groups, in which the active hydrogen groups are blocked (blocked). Examples thereof include blocked products of polycarboxylic acids, polyamines, amine-based polyols, and alkanolamines. Of these, preferred are blocked products of compounds having two active hydrogen groups, for example, those obtained by blocking dicarboxylic acids and diamines. Preferred among these are those in which diamines are blocked. If necessary, a blocked product having three or more active hydrogen groups can be used. In this case, the amount of the blocked product having three or more active hydrogen groups is 30% by weight or less of the blocked product having two active hydrogen groups.

The polycarboxylic acids used in (C) include the aliphatic dicarboxylic acids and aromatic dicarboxylic acids described in the section (B2).

The polyamine used in (C) includes:
Aromatic diamine [diethyltoluenediamine, 2,4 or 2,6-dimethylthiotoluenediamine, etc.], alicyclic diamine [4,4′-diamino-3,3′-dimethyldicyclohexylmethane, 4,4′-diamino −3,
3′-dimethyldicyclohexyl, diaminocyclohexane, isophoronediamine, etc.] and aliphatic diamines [1,2-ethylenediamine, 1,6-hexanediamine]. Preferred among these are alicyclic diamines.

Examples of the blocking agent for blocking the polycarboxylic acid include mono- or dicarboxylic acids. They may be aliphatic, alicyclic or aromatic. Specific examples include the dicarboxylic acids described in the section (B2).

As blocking agents for blocking the polyamine, acetone and methyl ethyl ketone (hereinafter referred to as M
EK), methyl isobutyl ketone (hereinafter MIBK)
, Etc.). Of these, acetone and MEK are preferred.

Examples of the method of blocking the polycarboxylic acid include a method of reacting a polycarboxylic acid with a monocarboxylic acid or a same or different polycarboxylic acid in the presence of a dehydrating agent, if necessary, to form an acid anhydride. it can.

The method of blocking the polyamine is not particularly limited, and a known method may be used. For example, a method of heating a mixture of a diamine and a ketone compound to remove generated water can be exemplified.

In the present invention, if necessary, the molecular weight of the thermoplastic urethane resin can be adjusted by using a polymerization terminator (E). Examples of (E) include monohydric alcohols [methyl alcohol, ethyl alcohol, cellosolve, phenol, etc.]} and monoamines {diethylamine, dibutylamine, diethanolamine, etc.}, among which monoamines are preferred.

The production of the thermoplastic urethane resin dispersion of the present invention may be carried out in the presence of the following thermoplastic resin. Examples of the thermoplastic resin include a thermoplastic (meth) acrylic acid (co) polymer, a thermoplastic polyester resin, and a mixture of two or more thereof. By including the thermoplastic resin, the thermal fusibility can be further improved.

The (meth) acrylic acid (co) polymer includes a polymer of (meth) acrylic acid and a copolymer composed of the acid and a comonomer. Examples of the comonomer include a (meth) acrylate monomer, an ethylenically unsaturated monomer other than the monomer, and a mixture of two or more thereof.

As the (meth) acrylate, for example, alkyl (meth) acrylate [methyl (meth) acrylate
Acrylate, butyl (meth) acrylate, trifluoroethyl (meth) acrylate, etc.]; heterocyclic (meth) acrylate [tetrahydrofurfuryl (meth) acrylate, etc.]; hydroxyalkyl (meth) acrylate [hydroxyethyl (meth) acrylate, Hydroxypropyl (meth) acrylate, etc.]; hydroxypolyoxyalkylene (C2-4 of oxyalkylene group) (meth) acrylate [hydroxypolyoxyethylene (meth) acrylate, hydroxypolyoxypropylene (meth) acrylate, etc.]; alkoxy (Alkoxy group preferably has 1 to 4 carbon atoms) Alkyl (Alkyl group preferably has 2 to 3 carbon atoms) (meth) acrylate [methoxyethyl (meth) acrylate, ethoxyethyl (meth) acryl Over preparative etc.]; amino group-containing (meth) acrylate [dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate]; and mixtures of two or more thereof. Of these, alkyl (meth)
Acrylate and hydroxyalkyl (meth) acrylate.

Examples of ethylenically unsaturated monomers other than (meth) acrylic acid ester monomers include organic acid vinyl esters [vinyl acetate, vinyl propionate, etc.]; unsaturated polybasic acid esters [maleic acid esters, fumaric acid esters] Aromatic vinyl monomers [styrene, p-methylstyrene, vinylpyridine, etc.]; other radically polymerizable monomers [(meth) acrylonitrile, (meth) acrylamide, phenylmaleimide, cyclohexylmaleimide, etc.] And mixtures of two or more of these. Among these, an aromatic vinyl monomer and (meth) acrylonitrile are preferable.

As the thermoplastic polyester resin,
The polyester resin comprising the dicarboxylic acid and glycol described in the section (B2) can be used.

Preferred among these thermoplastic resins are (co) polymers of alkyl or hydroxyalkyl (meth) acrylate. Examples of the comonomer constituting the copolymer include an aromatic vinyl monomer and other radically polymerizable monomers, and among them, styrene and (meth) acrylonitrile are preferable, and the ratio of the comonomer is (meth) It is usually 20 to 80% by weight based on the acrylate copolymer. The number average molecular weight of the thermoplastic resin is not particularly limited, but is usually 1000 to 10
It is 100,000, preferably 10,000 to 500,000.

The thermoplastic resin comprises (B), (B1), (B
It is preferable to produce a dispersion by incorporating the compound in any one of 2). The content of the thermoplastic resin is usually 0 to 100 parts by weight, preferably 0 to 50 parts by weight, based on 100 parts by weight of the thermoplastic urethane resin powder.

As a method for incorporating the thermoplastic resin into (B), (B1) or (B2), for example, (meth)
Taking acrylic acid (co) polymer as an example, (B) and (B1)
Alternatively, a method in which (meth) acrylic acid and (meth) acrylate are copolymerized in the presence of (B2) by using a radical polymerization initiator, if necessary, can be exemplified. The (meth) acrylic acid (co) polymer synthesized in advance may be mixed with (B), (B1) or (B2) in the presence of an organic solvent, if necessary.

Next, a method for producing the thermoplastic urethane resin dispersion of the present invention will be described. For example, (B) containing (C) is dispersed in a water containing (A) with a dispersing machine, and (B) is reacted with water and / or (C) to produce (C) which has been previously mixed with water. (B) containing (E) is dispersed in water containing (A) with a dispersing machine,
(B) is reacted with water and / or (C) and (E) to prepare a mixture of (B) and (E) containing (C) mixed in advance in water containing (A). Dispersing with a disperser, (B) is reacted with water and / or (C) and (E), and the mixture of (B) containing the production method (C) and the thermoplastic resin is
Dispersing in water containing (A) with a dispersing machine, and reacting (B) with water and / or (C) to produce a premixed (B) containing (C) and (E) and thermoplastic The mixture of resins is dispersed with a disperser in water containing (A), and (B) is dispersed in water and / or (C).
And (E) are reacted with each other to prepare a premixed (B) thermoplastic resin and (E)
Is dispersed in water containing (A) with a disperser, and (B) is reacted with water and / or (C) and (E) to produce

As an example of the conditions in each step of the batch method, the amount of (A) used is usually 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of water. Outside this range, a resin powder or a dispersion having a preferable particle size cannot be obtained. Further, (A) to 100 parts by weight of (B)
And the amount of the dispersion stabilizer liquid composed of water is usually 50 to 10
00 parts by weight, preferably 100 to 1000 parts by weight. Outside this range, the dispersion state of (B) is poor, so that a resin powder having a preferable particle size cannot be obtained. If necessary, (B) may be heated to 40 to 100 ° C. to reduce the viscosity, and a solvent such as an ester solvent, a ketone solvent, a chlorine solvent, or an aromatic solvent may be added.

In the present invention, the amount of the chain extender (C) to be used is generally 0.5 to 0.5 per 1 equivalent of the isocyanate group of (B).
1.5 equivalents, preferably 0.7 to 1.2 equivalents. Outside this range, a resin powder having good mechanical properties cannot be obtained. The amount of the reaction terminator (E) to be used is generally 0.03 to 0.4 equivalent, preferably 0.05 to 0.3 equivalent, per 1 equivalent of the isocyanate group of (B). Outside this range, good mechanical properties cannot be obtained.

The method for dispersing (B) in the water containing (A) is not particularly limited, and known equipment such as a low-speed shearing type, a high-speed shearing type, a friction type, a high-pressure jet type, and an ultrasonic type can be used. Of these, a high-speed shearing type is preferred.
When a high-speed shearing disperser is used, the number of revolutions is not particularly limited, but is generally 1,000 to 30,000 rpm, preferably 2,000 to 10,000 rpm. The dispersion time is not particularly limited, but is usually 0.1 to 5 minutes. If the number of rotations and the dispersion time are outside these ranges, a resin powder having a preferable particle size cannot be obtained.

The reaction time of (B) with (C) and (E) is not particularly limited, but is usually 1 hour to 40 hours, preferably 5 hours to 20 hours if the reaction temperature is 30 ° C. is there. Outside this range, the thermal fusibility and mechanical strength of the resin powder will be poor. In the production method of the present invention, the reaction temperature is usually 0 to 80 ° C, preferably 20 to 60 ° C. When the reaction temperature exceeds 80 ° C., coalescence of dispersed resin powders occurs.

The dispersion is filtered using a known apparatus such as a press filter, a spacula filter, a centrifugal separator and the like, and the obtained powder is dried to obtain a thermoplastic urethane resin powder. Drying of the obtained powder can be carried out using known equipment such as a circulating drier, a spray drier and a fluidized bed drier.

The resin powder obtained from the dispersion according to the present invention may contain, if necessary, known pigments, release agents, dyes, weathering stabilizers, lubricants, plasticizers, coupling agents, heat stabilizers,
A flame retardant or the like may be added. The method of adding these is not particularly limited, and may be added during the production of the dispersion.

When the thermoplastic urethane resin powder or the thermoplastic resin-containing thermoplastic urethane resin powder obtained by the production method of the present invention is used for slush molding,
It is preferable to use a powder having an average particle diameter of usually 10 to 300 μm and a repose angle of usually 40 ° or less. If the average particle size is less than 10 μm, the powder is scattered and the working environment is deteriorated, and if it exceeds 300 μm, many pinholes are generated on the surface of the molded product. Also, the angle of repose is 40
Exceeding the degree, the fluidity of the powder decreases and the moldability deteriorates,
The thickness of the molded product becomes uneven. The average particle size referred to here is the process particle size distribution measurement system TSUB-TEC.
300 (manufactured by Nippon Mining Co., Ltd.). The angle of repose can be determined with a powder tester (manufactured by Hosokawa Micron Corporation).

The melt flow rate of the thermoplastic urethane resin powder or the thermoplastic resin-containing thermoplastic urethane resin powder is 30 g or more / 10 minutes (200 ° C., 2.16 kg load), and preferably 30 to 1000 g / 10 minutes. Outside of this range, appropriate fluidity cannot be obtained and a satisfactory molded product cannot be obtained.

[0057]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. In the following description, "parts" indicates parts by weight and "%" indicates% by weight.

Production Example 1 Polycaprolactone polyol (molecular weight: 2000) 787 was placed in a four-necked flask equipped with a stir bar and a thermometer.
Parts, 800 parts of polyether diol (molecular weight 4000, EO content 50% by weight, PO content 50% by weight)
It dehydrated under reduced pressure at 120 ° C. The water content after dehydration was 0.05%. Next, 55.5 parts of HDI and 65.5 parts of hydrogenated MDI
And 0.6 part of dibutyltin dilaurate are added.
The reaction was performed at a temperature of 5 ° C. for 5 hours. The obtained product is referred to as [dispersion stabilizer 1].

Production Example 2 1 part of [Dispersion Stabilizer 1] was dispersed in 100 parts of water to obtain a milky white liquid. This is designated as [dispersion liquid 1].

Production Example 3 One part of polyvinyl alcohol [“PVA-235” manufactured by Kuraray Co., Ltd.] was dissolved in 100 parts of water. This is designated as [dispersion liquid 2].

Production Example 4 2000 parts of polycaprolactone diol having a hydroxyl value of 56 [“Placcel L220AL”, manufactured by Daicel Chemical Industries, Ltd.] was charged into a four-necked flask equipped with a stir bar and a thermometer, and the pressure was reduced to 3 mmHg. One below
Dehydration was performed by heating to 10 ° C. for 1 hour. Then IPDI
457 parts were charged and reacted at 110 ° C. for 10 hours to obtain a urethane resin having an isocyanate group at a terminal. The free isocyanate content of the urethane resin was 3.6%. This is referred to as [urethane resin 1].

Production Example 5 "Placcel L220AL" having a hydroxyl value of 56 was placed in a four-necked flask equipped with a stir bar and a thermometer.
Then, 00 parts were charged and heated to 110 ° C. under a reduced pressure of 3 mmHg to perform dehydration for 1 hour. Subsequently, 457 parts of IPDI were charged, and the reaction was carried out at 110 ° C. for 10 hours to obtain a urethane resin having an isocyanate group at a terminal. Further, 1052 parts of methyl acrylate and 50 parts of styrene were added to the urethane resin.
0 parts and 3 parts of azobisisovaleronitrile (hereinafter abbreviated as AIVN) were added, and polymerization was carried out at 70 to 110 ° C. for 3 hours. The free isocyanate content of the polymethyl acrylate-containing urethane resin was 1.2%. This is designated as [urethane resin 2].

Production Example 6 50 parts of ethylenediamine and 50 parts of MIBK were charged into a four-necked flask in which a stir bar and a thermometer were set.
The reaction was performed at a temperature of 5 ° C. for 5 hours. The obtained ketimine compound is referred to as [chain extender 1].

Production Example 7 Diethylenetoluenediamine (hereinafter abbreviated as DETDA) 3 was placed in a four-necked flask equipped with a stirring rod and a thermometer.
00 parts and 70 parts of MEK were charged and reacted at 30 ° C. for 10 hours. The obtained ketimine compound is referred to as [chain extender 2].

Example 1 In a beaker, 50 parts of [urethane resin 1] and 6 parts of [chain extender 1] were mixed, and 250 parts of [dispersion liquid 1] were added. Then, an ultra disperser (Yamato Scientific Co., Ltd.) was used. Was mixed at 9000 rpm for 1 minute. After mixing, the mixture was charged into a four-necked flask equipped with a stir bar and a thermometer, and reacted at 50 ° C. for 10 hours. Next, 1 part of an anti-blocking agent [“Syloid 978”, manufactured by Fuji Devison Chemical Co., Ltd.] and a light stabilizer [“DIC-T”
BS ", manufactured by Dainippon Ink and Chemicals, Inc.], filtered and dried to prepare a resin powder (F1).

Example 2 50 parts of [urethane resin 2] and 4 parts of [chain extender 1] were mixed in a beaker, and 250 parts of [dispersion liquid 1] were added. Then, an ultra disperser (Yamato Scientific Co., Ltd.) was used. Was mixed at 9000 rpm for 1 minute. Thereafter, a resin powder (F2) was obtained in the same manner as in Example 1.

Example 3 In Example 2, [dispersion 2] was used instead of [dispersion 1].
Resin powder (F) was prepared in the same manner as in Example 1 except that
3) was obtained.

Example 4 Same as Example 1 except that 4 parts of [Chain extender 1] were replaced by 3 parts of [Chain extender 2] and 0.3 part of di-n-butylamine in place of 4 parts of [Chain extender 1]. Thus, a resin powder (F4) was obtained.

Comparative Example 1 When isophoronediamine (hereinafter abbreviated as IPDA) was used in place of [Chain extender 1] in Example 1, the elongation reaction was completed immediately after urethane resin 1 and IPDA were mixed, and a resin was formed. Resin powder (F5) which cannot be dispersed in dispersant 1
Was not obtained.

Comparative Example 2 After adding 250 parts of [Dispersion Liquid 1] to 50 parts of [Urethane Resin 1], the mixture was mixed for 1 minute at 9000 rpm using an Ultra Desparser (manufactured by Yamato Scientific Co., Ltd.). After mixing, the mixed solution was charged into a four-necked flask in which a stir bar and a thermometer were set, and then 5 parts of DETDA was charged, and 50 ° C.
For 10 hours. Next, 1 part of an antiblocking agent ["Syloid 244", manufactured by Fuji Devison Chemical Co., Ltd.] and 0.5 part of a light-resistant stabilizer ["DIC-TBS", manufactured by Dainippon Ink and Chemicals, Ltd.] were added, followed by dehydration and drying to obtain a resin powder ( F6) was obtained.

Physical Property Measurement Example 1 The resin powders (F1) obtained in Examples 1 to 4 and Comparative Example 2
(F4) and (F6) were brought into contact with a mold heated to 260 ° C., melted by heat, and then cooled with water to form a molded sheet, and the breaking strength and elongation (JIS K6301) were measured. Table 1 shows the results. Note that the resin powder (F6) did not melt and the physical properties of the sheet could not be measured.

[0072]

Physical property measurement example 2 Resin powder (F1) obtained in Examples 1 to 4 and Comparative Example
(F4), (F6) and commercial PVC were contacted with a mold heated to 260 ° C. to form a film. Next, a urethane foam-forming component is added and foamed and adhered.
Heat treatment was performed in a circulating air dryer at 20 ° C. for 500 hours. The urethane foam was removed from the molded article thus produced, and the elongation at break (JIS K6301) of each molded article was measured and the degree of discoloration was observed. Table 2 shows the results.
Shown in

[0074] The criteria for determining the degree of discoloration are as follows. (Visual judgment) ○: no discoloration, Δ: slight discoloration, ×: remarkable discoloration

Physical property measurement example 3 Each lash molded product described in physical property measurement example 2 was placed in a carbon arc fade meter at a black panel temperature of 83 ° C.
Treated for 00 hours. After the treatment, the urethane foam is removed from the molded product, and the elongation percentage of each molded product (JIS K6301)
Was measured and the degree of discoloration was observed. The results are shown in Table 3.

[0076]

[0077]

The method of the present invention has the following effects. 1. Since a thermoplastic urethane resin dispersion can be easily produced in water, a powdered thermoplastic urethane resin dispersion can be produced at a lower cost than conventional production methods. 2. Since the reaction between the isocyanate group-containing urethane resin and water can be suppressed, it is possible to produce a thermoplastic urethane resin powder having excellent heat melting property as compared with a conventional production method. 3. A thermoplastic urethane resin powder that gives a flexible and durable film can be produced. Because of the above effects, the resin powder obtained by the method of the present invention is extremely useful as various molding materials such as interior materials for automobiles. It can also be applied to powder coatings and various hot melt adhesives.

Claims (4)

(57) [Claims] 1. In the presence of water and a dispersion stabilizer (A),
A method for producing a thermoplastic urethane resin dispersion, comprising reacting a urethane resin (B) having an isocyanate group with a blocked chain extender (C). 2. The dispersion stabilizer (A) is composed of a part (A1) having an affinity for the urethane resin (B) and a part (A2) having a hydrophilic property.
2. The method according to claim 1, having 12 solubility parameters. 3. The method according to claim 1, wherein (C) is a ketimine compound (D). 4. The process according to claim 1, wherein (C) contains a reactive terminator (E).