JP4936209B2 - Method for producing powdered thermoplastic polyurethane urea resin - Google Patents

Description

  The present invention relates to a method for producing a powdered thermoplastic polyurethane urea resin suitably used for slush molding or the like.

The slush molding method has a complicated shape and can efficiently form a product having a uniform wall thickness, and is therefore widely used in applications such as automobile interior materials.
Recently, a powdered thermoplastic polyurethane resin excellent in flexibility has been adopted as a slush molding material.

As a method for producing a powder polyurethane resin (polyurethane urea resin) for slush molding, the present applicant can disperse in a non-aqueous dispersion medium. The manufacturing method including the process of making the isocyanate group terminal prepolymer made to react with water and chain-extending is proposed (refer patent document 1).
Patent Document 1 also discloses that a part of the isocyanate group of the isocyanate group-terminated prepolymer is reacted with a low molecular polyol and the like, and then the remainder of the isocyanate group is reacted with water.
JP 2004-161866 A

  In addition, the applicant of the present invention is a non-aqueous system for producing a powder polyurethane resin (polyurethane urea resin) for slush molding that has excellent meltability, is less likely to cause blooming, and is capable of obtaining a molded product that is less likely to be bent and wrinkled. Has proposed a production method comprising a step of reacting a part of an isocyanate group-terminated prepolymer dispersed in a dispersion medium with a specific monofunctional active hydrogen compound and then reacting with water to extend the chain (special feature). Application 2005-257900).

However, in the production process of powdered thermoplastic polyurethane urea resin, the isocyanate and water react locally (the urea bond produced by the reaction between isocyanate and water is localized by its strong hydrogen bonding force). In other words, it is said that it has an ultra-high molecular weight in a hardly fusible substance (gel permeation chromatography (hereinafter abbreviated as “GPC”)) having an excessive molecular weight due to the promotion of local urea reaction, etc. There is a problem that a powdered thermoplastic polyurethane urea resin containing such a hardly-fusible substance is extremely inferior in melt moldability.
In addition, since non-aqueous organic solvents used as dispersion media are generally highly flammable, there is a problem that expensive equipment is required to ensure safety during industrial production. .

  In the method of reacting a part of the isocyanate group of the isocyanate group-terminated prepolymer with a low-molecular polyol and the like and then reacting the remainder of the isocyanate group with water, the resin is controlled by controlling the molar ratio of the isocyanate group and the active hydrogen group. There is a problem that it is difficult to control the molecular weight (a molecular weight design method that has been widely used). This is to ensure that a predetermined amount (equivalent to the remainder of the isocyanate group) of the active hydrogen group reacts with the remainder of the isocyanate group by evaporating part of the water during the reaction or subjecting it to a side reaction. It is because it is not possible.

The object of the present invention is a powdered thermoplastic polyurethane urea resin capable of obtaining a molded article having excellent mechanical properties, abrasion resistance and crease resistance, etc., which is easy to control the molecular weight and melted. An object of the present invention is to provide a method by which a powdery thermoplastic polyurethane urea resin having excellent moldability can be produced reliably and inexpensively.
Another object of the present invention is to provide a method capable of reliably producing a powdered thermoplastic polyurethane urea resin capable of obtaining a molded article having excellent blooming resistance.
Still another object of the present invention is to provide a method capable of reliably and safely producing a thermoplastic polyurethane urea resin suitable as a powder material for slush molding.

The production method according to the present invention is a method for producing a powdered thermoplastic polyurethane urea resin, comprising the following first to third steps, and a polymer polyol that reacts with an organic polyisocyanate in the first step. The number of moles of active hydrogen groups having is A, the number of moles of dialkylamine having a hydrocarbon group having 4 to 12 carbon atoms that reacts with a part of the isocyanate groups is x1, and the water that reacts with the remainder of the isocyanate groups in the second step When the number of moles of the active hydrogen group is x2, the ratio [(x1 + x2) / A] is 0.3 to 1.5, and the ratio (x1 / x2) is 5 to 35/95 to 65. Features.

First step: A step of preparing an isocyanate group-containing prepolymer by reacting a polymer polyol and a dialkylamine having a hydrocarbon group having 4 to 12 carbon atoms with an organic polyisocyanate.
Second step: Dispersing the polyurethane urea resin by dispersing the isocyanate group-containing prepolymer in water in the presence of a dispersion stabilizer and reacting the remaining isocyanate groups of the isocyanate group-containing prepolymer with the active hydrogen groups of water. A step of preparing a liquid.
Third step: A step of preparing a powdery thermoplastic polyurethane urea resin by separating and drying the polyurethane urea resin from the obtained dispersion.

Further, the ratio [(x1 + x2) / A] is preferably 0.3 to 1.2, and the ratio (x1 / x2) is preferably 5 to 20/95 to 80.
The ratio [(x1 + x2) / A] is preferably 0.75 to 1.5, and the ratio (x1 / x2) is preferably 10 to 35/90 to 65.
Furthermore, the organic polyisocyanate used in the first step is preferably hexamethylene diisocyanate.

(1) When producing an isocyanate group-containing prepolymer, the molecular weight can be easily controlled by reacting a part of the isocyanate group in the reaction system with a dialkylamine having a hydrocarbon group having 4 to 12 carbon atoms. In both cases, formation of a hardly fusible substance having an excessive molecular weight (for example, Mn of 500,000 or more in GPC analysis) is suppressed. As a result, the melt moldability of the obtained powdered thermoplastic polyurethane urea resin is remarkably improved.
(2) By reacting the remainder of the isocyanate group of the isocyanate group-containing prepolymer with water, a urea group is introduced into the resulting resin, and as a result, the resulting molded product of a powdered thermoplastic polyurethane urea resin is obtained. Excellent crease resistance, mechanical properties and wear resistance are exhibited.
(3) Since the carbon number of the hydrocarbon group in the dialkylamine is 4 to 12, the molecular weight of the obtained powdered thermoplastic polyurethane urea resin can be reliably controlled, and the molded product of the powdered thermoplastic polyurethane urea resin. Is excellent in blooming resistance.
(4) Since it is not necessary to use a non-aqueous dispersion medium (organic solvent), a powdery thermoplastic polyurethane urea resin can be produced safely and with inexpensive equipment .

The manufacturing method according to the present invention will be described.
<Isocyanate group-containing prepolymer>
The isocyanate group-containing prepolymer used in the production method of the present invention is obtained by reacting a polymer polyol and a dialkylamine having a hydrocarbon group having 4 to 12 carbon atoms (hereinafter referred to as dialkylamine) with an organic polyisocyanate. Is obtained.

The number average molecular weight of the polymer polyol used for obtaining the isocyanate group-containing prepolymer is 500 or more, preferably 1,000 to 5,000.
The kind of the polymer polyol is not particularly limited, and examples thereof include polyester polyol, polyester amide polyol, polyether polyol, polyether ester polyol, polycarbonate polyol, polyolefin polyol, and the like. Two or more kinds can be used in combination.

  Examples of the polyester polyol and polyester amide polyol include polycarboxylic acid, polycarboxylic acid derivatives such as polycarboxylic acid, dialkyl esters of polycarboxylic acid, acid anhydrides, and acid halides, low molecular polyols, low molecular weight polyamines having a number average molecular weight of less than 500, It is obtained by a reaction with a low molecular active hydrogen group-containing compound such as a low molecular amino alcohol.

  Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic anhydride, hexahydroterephthalic acid, hexahydroisophthalic acid and the like.

  Low molecular polyols include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol (hereinafter 1,4-BD). Abbreviation), 1,5-pentanediol, 1,6-hexanediol (hereinafter abbreviated as 1,6-HD), 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octane Diol, 1,9-nonanediol, 3,3-dimethylolheptane, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-ethyl-1,3-propanediol, 2-normalpropyl- 1,3-propanediol, 2-isopropyl-1,3-propanediol, 2-normalb 1,3-propanediol, 2-isobutyl-1,3-propanediol, 2-tertiarybutyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2, 2-diethyl-1,3-propanediol, 2-ethyl-2-normalpropyl-1,3-propanediol, 2-ethyl-2-normalbutyl-1,3-propanediol, 2-ethyl-3-ethyl -1,4-butanediol, 2-methyl-3-ethyl-1,4-butanediol, 2,3-diethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2 , 3,4-triethyl-1,5-pentanediol, trimethylolpropane, dimethylolpropionic acid, dimethylolbutanoic acid, dimer acid diol, Phosphorus, pentaerythritol, alkylene oxide adduct of bisphenol A and the like.

  Examples of the low molecular weight polyamine having a number average molecular weight of less than 500 include ethylenediamine, hexamethylenediamine, xylylenediamine, isophoronediamine, and ethylenetriamine.

Examples of the low molecular amino alcohol having a number average molecular weight of less than 500 include monoethanolamine, diethanolamine, and monopropanolamine.
Also suitable are polyester polyols such as lactone polyester polyols obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone. Can be used.

  Examples of the polyether polyol include polyethylene glycol, polypropylene ether polyol, and polytetramethylene ether polyol.

  Examples of polyether ester polyols include polyester polyols produced from the above polyether polyols and the above polycarboxylic acid derivatives.

  Polycarbonate polyols include those obtained by deethanol condensation reaction of low molecular polyol and diethyl carbonate; dephenol condensation reaction of low molecular polyol and diphenyl carbonate; deethylene glycol condensation reaction of low molecular polyol and ethylene carbonate, etc. Can be mentioned. Examples of the low molecular polyol used for obtaining the polycarbonate polyol include low molecular polyols exemplified as those for obtaining the polyester polyol.

  Specific examples of the polyolefin polyol include a hydroxyl group-terminated polybutadiene, a hydrogenated product thereof, and a hydroxyl group-containing chlorinated polyolefin.

  Preferred polymer polyols are polyester polyols, polyether polyols, and polycarbonate polyols having a number average molecular weight of 1,000 to 5,000 because of the good physical properties and feel of the resulting molded product. A polyester polyol having an average molecular weight of 1,000 to 5,000 is preferable, and a polyester polyol using an aromatic dicarboxylic acid as an acid component in an amount of 20 mol% to less than 60 mol% is particularly preferable.

  Examples of the organic polyisocyanate used for obtaining the isocyanate group-containing prepolymer include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, tetra Methyl xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2, 2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenol Aromatic diisocyanates such as diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3′-dimethoxydiphenyl-4,4′-diisocyanate, tetramethylene diisocyanate, hexamethylene Alicyclics such as diisocyanates (hereinafter abbreviated as HDI), aliphatic diisocyanates such as decamethylene diisocyanate and lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylene diisocyanate In addition to aromatic diisocyanates, their polymers, their polymeric materials, urethane-modified products, and allophanate-modified products , Urea modified products, biuret modified products, carbodiimide-modified products, uretonimine modified product, uretdione modified product, an isocyanurate modified product, and further mixtures of two or more thereof. In the present invention, in consideration of the weather resistance of the molded article, aliphatic and / or alicyclic diisocyanates are preferable, HDI, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate are particularly preferable, and HDI is most preferable.

  As a ratio of the polymer polyol used for obtaining the isocyanate group-containing prepolymer and the organic polyisocyanate, the molar ratio of the latter isocyanate group to the hydroxyl group possessed by the former ([NCO] / [OH]) is 1. The ratio is preferably from 05 to 5.0, more preferably from 1.3 to 2.5.

The reaction of the polymer polyol, the dialkylamine and the organic polyisocyanate is preferably performed in the absence of an organic solvent and / or a plasticizer that can substantially dissolve the resulting isocyanate group-containing prepolymer. In order to decrease the viscosity of the isocyanate group-containing prepolymer and facilitate dispersion in water, the pretreatment may be performed in the presence (dissolved state) of the organic solvent and the plasticizer.

<Dialkylamine>
The carbon number of the “hydrocarbon group” possessed by the dialkylamine is 4 to 12, preferably 4 to 11, and more preferably 4 to 9.
When the carbon number of the dialkylamine is less than 4, the molecular weight of the resulting resin cannot be controlled (see Comparative Example 9). On the other hand, when a dialkylamine having more than 12 carbon atoms is used, blooming is likely to occur in a molded product of the resulting resin (see Comparative Example 8).
Specific examples of the dialkylamine having a hydrocarbon group having 4 to 12 carbon atoms include di-n-butylamine, di-isobutylamine, di-t-butylamine, di-n-hexylamine, di-cyclohexylamine, di- Examples thereof include n-octylamine, di-2-ethylhexylamine, di-n-nonylamine, di-dodecylamine and the like, and these can be used alone or in combination of two or more.

The dialkylamine is preferably reacted with an organic polyisocyanate simultaneously with the polymer polyol, but may be reacted with an isocyanate group-containing intermediate obtained by reacting the polymer polyol and the organic polyisocyanate in advance.

<Water>
In the production method of the present invention, water plays the role of a chain extender as well as a dispersion medium. The active hydrogen group which water has here reacts with the remainder of the isocyanate group which an isocyanate group containing prepolymer has.
The reaction between the isocyanate group-containing prepolymer (the remainder of the isocyanate group) and water (active hydrogen group) is carried out in water.

<Organic solvent>
Examples of organic solvents that can be used to lower the viscosity of the isocyanate group-containing prepolymer include polar organic media such as THF, acetone, methyl ethyl ketone (hereinafter abbreviated as MEK), N-methylpyrrolidone, and N, N-dimethylformamide. .
In order to finally obtain a powdered thermoplastic polyurethane urea resin, it is necessary to remove these organic solvents from the resin, and THF, acetone, and MEK are preferable because of easy removal. Of these, acetone and MEK are particularly preferable.

<Plasticizer>
Plasticizers that can be used to reduce the viscosity of the isocyanate group-containing prepolymer include dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate , Diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, myristyl benzyl phthalate, etc .; di- (2-ethylhexyl) isophthalate, di Isophthalic acid esters such as isooctyl isophthalate; tetrahydrophthalic acid esters such as di-2-ethylhexyl tetrahydrophthalate Di- (2-ethylhexyl) adipate, dibutoxyethyl adipate, adipate esters such as diisononyl adipate; azelaic acid esters such as di-n-hexyl azelate, di- (2-ethylhexyl) azelate; Sebacic acid esters such as n-butyl sebacate; maleic acid esters such as di-n-butyl maleate and di- (2-ethylhexyl) maleate; di-n-butyl fumarate and di- (2-ethylhexyl) fumarate Fumaric acid esters such as tri (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, etc .; tetra- (2-ethylhexyl) pyromellitate, tetra-n -Pyro such as octyl pyromellitate Litates; citrates such as tri-n-butyl citrate and acetyl tributyl citrate; itaconates such as dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di- (2-ethylhexyl) itaconate Oleic acid esters such as glyceryl monooleate and diethylene glycol monooleate; ricinoleic acid derivatives such as glyceryl monoricinoleate and diethylene glycol monoricinoleate; stearic acid esters such as glycerin monostearate and diethylene glycol distearate; Other fatty acid esters such as pelargonate and pentaerythritol fatty acid ester; tributoxyethyl phosphate, triphenyl phosphate, tricresyl Phosphate esters such as phosphate, diphenyldecyl phosphate, diphenyloctyl phosphate; aromatic monocarboxylic acid diesters of polyalkylene glycol such as diethylene glycol dibenzoate, triethylene glycol dibenzoate, polyethylene glycol dibenzoate; triethylene glycol di- ( 2-ethylhexoate), glycol derivatives such as tripropylene glycol dibenzoate, dibutylmethylene bisthioglycolate; glycerol derivatives such as glycerol monoacetate, glycerol triacetate, glycerol tributyrate; epoxidized soybean oil, epoxybutyl stearate , Di-2-ethylhexyl epoxyhexahydrophthalate, diisodecyl epoxyhexahydrophthalate Epoxy triglyceride, epoxidized oleic acid octyl, epoxy derivatives such as epoxidized decyl oleate; other adipic acid-based polyester, sebacic acid-based polyester, phthalic acid-based polyester and mixtures of two or more thereof, and the like.
The aromatic monocarboxylic acid diester of the polyalkylene glycol is preferable from the viewpoint of suppressing blooming that may occur in the molded product from the resin obtained and low temperature characteristics of the molded product, particularly brittle fracture at low temperatures.
The amount of the plasticizer used is usually 30% or less, and preferably 25% or less, as a ratio to the powdery thermoplastic polyurethaneurea resin obtained.

<Dispersion stabilizer>
In addition, it is preferable to use a dispersion stabilizer from the viewpoint of uniformly dispersing the high molecular isocyanate group-containing prepolymer in water. The dispersion stabilizer has a structure in which a portion having a high affinity with the isocyanate group-containing prepolymer and a portion having a high affinity for water are present in one molecule.

The dispersion stabilizer is not particularly limited, and known ones can be used. Specific examples thereof include a cellulose-based water-soluble resin such as a methylcellulose-based or hydroxyethylcellulose-based resin, a polyvinyl alcohol, a polyacrylate, and a urethane comprising active hydrogen-containing polybutadiene. Resin.
In addition to this, a reaction product of an organic oligomer having an unsaturated bond and an ethylenically unsaturated monomer having a hydrophilic side chain is preferable.
As this organic oligomer, for example, a polyester produced by using a polymer of a diene monomer such as polybutadiene or polyisoprene, a glycol or unsaturated diglycolic acid containing a unsaturated bond-containing glycol or a dibasic acid. Polyester polyols produced using polyols, unsaturated bond-containing glycols as starting materials, hydroxyl-terminated polyesters having a number average molecular weight of 2,000 or less, polyethers, polycarbonates, etc., and esterification reaction of unsaturated bond-containing dicarboxylic acids In addition to the resulting polyol, polyolefin polyol and the like can be mentioned.
Examples of the unsaturated bond-containing glycol include 2-butene-1,4-diol, glycerin monoallyl ether, and the like. Examples of the unsaturated bond-containing dicarboxylic acid include maleic acid, fumaric acid, and itaconic acid.

Examples of the method for adding the dispersion stabilizer include a method of mixing in the isocyanate group-containing prepolymer in the first step and / or a method of mixing in water.
Moreover, it is preferable that it is 0.1-10 mass% with respect to the isocyanate group containing prepolymer as the usage-amount of a dispersion stabilizer, More preferably, it is 0.5-5 mass%.

<Ratio of dialkylamine and water>
In the present invention, the ratio of dialkylamine to water is such that when the number of moles of dialkylamine (number of moles of reaction) is x1, and the number of moles of active hydrogen groups having water (number of moles of reaction) is x2, the ratio (x1 / x2) is set to 5/95 to 35/65.
When this ratio (x1 / x2) is less than 5/95, that is, when the proportion of dialkylamine is too small, formation of a hardly fusible substance having an excessive molecular weight cannot be suppressed, and the resulting powdery heat The plastic polyurethane urea resin cannot exhibit suitable melt moldability (particularly leveling properties and pinhole prevention performance) (see Comparative Example 3 described later). On the other hand, when the ratio (x1 / x2) exceeds 35/65, that is, when the ratio of dialkylamine is excessive, the molded product made of the polyurethane urea resin obtained has good crease resistance, wear resistance, etc. Cannot be given (see Comparative Example 4 described later).

In the first step, the ratio between the polymer polyol used to obtain the isocyanate group-containing prepolymer and the organic polyisocyanate is the molar ratio of the latter isocyanate group to the former hydroxyl group ([NCO] / [NCO] / [ OH]) is 1.3 to 2.5.
When the molar ratio ([NCO] / [OH]) is less than 1.3, a sufficient concentration of NCO groups cannot be introduced into the resulting isocyanate group-containing prepolymer, and this can be obtained using this. It is not possible to introduce a sufficient concentration of urea groups into the polyurethane urea resin obtained, and it is impossible to impart excellent crease resistance, mechanical properties, and wear resistance to the molded product of the resin (described later). Comparative Example 1).
On the other hand, when the molar ratio ([NCO] / [OH]) exceeds 2.5, an excess amount of NCO groups is introduced into the resulting isocyanate group-containing prepolymer, and a polyurethane urea resin obtained by using this is used. The concentration of urea groups in the inside becomes excessive, the production of a hardly-fusible substance due to side reactions cannot be suppressed, and the melt moldability is lowered (see Comparative Example 2 described later).

In the first step, a conventionally known urethanization catalyst or the like can be used as necessary. Examples of the urethanization catalyst include triethylenediamine, bis-2-dimethylaminoethyl ether, dibutyltin dilaurate, lead naphthenate, iron naphthenate, copper octenoate, and bismuth catalysts.
The reaction conditions in the first step vary depending on whether a low-boiling organic solvent is used in combination or when a low-boiling dialkylamine is used, but it is preferably 1 to 4 hours at 40 to 110 ° C. Preferably it is set as 2-3 hours at 50-100 degreeC.

  The second step is also a step of extending the molecular chain by reacting water after dispersing the isocyanate group-containing prepolymer in water. Specifically, after blending a dispersion stabilizer in the isocyanate group-containing prepolymer composition obtained in the first step, the mixture is dispersed in water and then reacted with an isocyanate group and water. is there.

In the dispersion of the isocyanate group-containing prepolymer obtained in the second step, the mass ratio of the dispersed phase (total amount of raw materials other than the dispersion medium) and the continuous phase (dispersion medium) is determined in consideration of production efficiency and production cost. The dispersed phase / continuous phase is preferably 10/90 to 80/20, more preferably 15/85 to 75/25, and still more preferably 20/80 to 70/30.
In addition, when preparing the dispersion liquid, it is necessary to use a known mechanical high-speed stirrer (such as a homomixer manufactured by PRIMIX Co., Ltd., a Cavitron manufactured by Eurotech Co., Ltd., an ultradisperser manufactured by Yamato Scientific Co., Ltd.). it can.

  Further, in the second step, the remaining isocyanate group of the isocyanate group-containing prepolymer is reacted with the active hydrogen group of water until the isocyanate group is completely consumed.

In the second step, the reaction temperature in the reaction between the isocyanate group of the isocyanate group-containing prepolymer and the active hydrogen group of water is preferably 40 to 85 ° C, more preferably 50 to 80 ° C. .
If the reaction temperature is too low, the reaction takes a long time. On the other hand, if the reaction temperature is too high, water and the like evaporate, and equipment such as a reflux device is required for the production apparatus.

In the present invention,
(1) Ratio [(x1 + x2) / A] is 0.3 to 1.2, and ratio (x1 / x2) is 5/95 to 20/80, and (2) Ratio [(x1 + x2) / A] is particularly preferably 0.75 to 1.5, and the ratio (x1 / x2) is particularly preferably 10/90 to 35/65.

<Third step>
The third step is a step of preparing a powdery thermoplastic polyurethane urea resin by separating and drying the polyurethane urea resin from the dispersion obtained in the second step.
Specifically, the polyurethane urea resin is separated from the dispersion medium by a filtration method or a decantation method, and then dried under normal pressure or reduced pressure at room temperature or warm.

<Powdered thermoplastic polyurethane urea resin>
The shape of the powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention is a true sphere with good fluidity (flowability during molding). Moreover, it is preferable that the angle of repose of the said powdery thermoplastic polyurethane urea resin is 35 degrees or less, More preferably, it is 20 degrees-33 degrees. When the angle of repose is excessive, the flowability at the time of molding is deteriorated, and molding defects are likely to occur.
In addition, the angle of repose of the powdered thermoplastic polyurethane urea resin produced by freeze-pulverizing the bulk resin exceeds 33 °.

The number average molecular weight (Mn) of the powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention is preferably 18,000 to 50,000, more preferably 20,000 to 45,000.
When the number average molecular weight (Mn) is too small, sufficient mechanical properties and durability cannot be imparted to the finally obtained molded product.
On the other hand, when the number average molecular weight (Mn) is excessive, suitable melt moldability cannot be exhibited (see Comparative Examples 1-2 and Comparative Example 8 described later).
Here, the “number average molecular weight (Mn) of polyurethane urea resin” refers to a value obtained from a peak other than the peak of ultra high molecular weight (Mn is 500,000 or more) by GPC measurement.

The weight average molecular weight (Mw) of the powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention is preferably 43,000-110,000, more preferably 47,000-100,000.
Here, the “weight average molecular weight (Mw) of the polyurethane urea resin” refers to a value obtained from a peak other than the peak of ultrahigh molecular weight by GPC measurement.

The average particle diameter of the powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention is 1,000 μm or less, preferably 10 to 500 μm, more preferably 90 to 200 μm.
If the average particle size is excessive, pinholes are likely to occur in the undercut portions and corner portions of the obtained molded product.
On the other hand, when the average particle size is excessive, flowability and powder breakage are deteriorated, and the thickness of the obtained molded product tends to be nonuniform.
Here, the “average particle size” refers to a cumulative percent value of 50% in a particle size distribution curve measured by a laser particle size analyzer.
The average particle size of the powdered thermoplastic polyurethane urea resin can be adjusted to be small by using the aforementioned organic solvent and / or plasticizer in combination with the isocyanate group-containing prepolymer.

  An additive can be added to the powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention, if necessary. Examples of such additives include pigments / dyes, antioxidants, ultraviolet absorbers, plasticizers, antiblocking agents, radical polymerization initiators, coupling agents, flame retardants, inorganic and organic fillers, lubricants, antistatic agents, and crosslinks. An agent etc. can be mentioned.

  Examples of the “plasticizer” here include the same ones that can be used in the first step.

“Pigments” include organic pigments such as insoluble azo pigments, soluble azo pigments, copper phthalocyanine pigments, quinacridone pigments; chromates, ferrocyan compounds, metal oxides, metal salts (sulfates, silicates, carbonates) And inorganic pigments such as metal powder and carbon black.
In general, pigments available as a colorant often contain a pigment dispersant to improve dispersibility.
Examples of the pigment dispersant include resin dispersants such as low molecular weight polyethylene and petroleum resin; inorganic dispersants such as silica and calcium carbonate; silane coupling agents and the like.
The addition amount of the pigment is usually 5% by mass or less, preferably 1 to 3% by mass with respect to the powdered thermoplastic polyurethane urea resin.

Examples of the “antioxidant” include phenol-based [2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, etc.], bisphenol-based [2,2′-methylenebis (4-methyl-6-t- Butylphenol) and the like] and phosphorus [triphenyl phosphite, diphenylisodecyl phosphite, etc.], and these can be used alone or in combination of two or more.
Examples of “ultraviolet absorbers” include benzophenone [2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, etc.], benzotriazole [2- (2′-hydroxy-5′-methylphenyl) benzotriazole, etc. ], Salicylic acid type [phenyl salicylate, etc.], hindered amine type [bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, etc.], and these may be used alone or in combination of two or more. Can be used.
The addition amount of the antioxidant and the ultraviolet absorber is usually 5% by mass or less, preferably 0.01 to 3% by mass with respect to the powdered thermoplastic polyurethane urea resin.

The “antiblocking agent” is not particularly limited, and examples thereof include known inorganic antiblocking agents and organic antiblocking agents.
Examples of the inorganic anti-blocking agent include silica, talc, titanium oxide, calcium carbonate, and the like. Examples of the organic anti-blocking agent include thermosetting resins having a particle diameter of 10 μm or less (for example, thermosetting polyurethane resin, guanamine type). Resin, epoxy resin, and the like) and thermoplastic resins having a particle diameter of 10 μm or less (for example, thermoplastic polyurethane urea resin, poly (meth) acrylate resin, polystyrene resin, etc.).
Of these, organic blocking inhibitors are preferred, and poly (meth) acrylate resins and polystyrene resins are particularly preferred.
The addition amount of the anti-blocking agent is usually less than 5% by mass, preferably 0.1 to 3% by mass with respect to the powdered thermoplastic polyurethane urea resin.

<Slush molding method>
The powdery thermoplastic polyurethane urea resin obtained by the production method of the present invention can be suitably used as a powder material for slush molding.

An example of the slush molding method is as follows.
First, a mold release agent is applied to a mold (mold), and then the mold is heated. Here, the release agent is applied at 60 ° C. or lower. Examples of the method for applying the release agent include an air spray method and a brush coating method. The heating temperature of the mold is usually 150 to 300 ° C, preferably 180 to 280 ° C. Examples of the heating method include a hot sand heating method and an oil heating method.

Next, the powder material (powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention) is charged into a mold and held (powdered) for 15 to 45 seconds to remove excess powder material, and then 200 The mold is placed in a heating oven at ˜400 ° C. and heated for 20 to 300 seconds, preferably 30 to 120 seconds, to complete melting of the powder material.
Then, the metal mold | die taken out from heating oven is cooled by the water cooling method etc., and a slush molding (for example, sheet | seat of 0.7-2 mm thickness) is obtained by removing from a mold.

Moreover, without taking out a slush molding (sheet), by introducing a polyurethane foam-forming material into the same mold, foaming it, and forming a core material made of polyurethane foam, then demolding, A member having a skin layer made of a slush molding (for example, an automobile instrument panel, a console box, an armrest, etc.) can be manufactured. Here, examples of the polyurethane foam include a flexible foam and a semi-rigid foam having a density of 0.02 to 0.5 g / cm ³ .

Examples of the present invention will be described below, but the present invention is not limited thereto.
[Preparation Example 1 (Preparation of dispersion stabilizer solution)]
A reactor having a capacity of 2 L equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube was charged with 565 g of adipic acid and 575 g of 3-methylpentanediol, and under conditions of 150 ° C. and normal pressure while flowing nitrogen gas And a polyester diol having a number average molecular weight of 1000 was synthesized.
Next, 100 g of the polyester diol and 150 g of diisononyl adipate were charged into a 1000 mL reactor equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube, and the temperature was raised to 80 ° C. while flowing nitrogen gas. And stirred. To this, 42 g of hexamethylene diisocyanate was added and reacted at 80 ° C. for 2 hours to prepare an isocyanate group-containing prepolymer. An additional 200 g of polyvinyl alcohol having a number average molecular weight of 1000 was added thereto and further reacted at 80 ° C. for 2 hours to obtain a dispersion stabilizer solution having a solid content of about 70%. Hereinafter, this is referred to as “dispersion stabilizer solution (1)”.

[Preparation Example 2 (Preparation of dispersion stabilizer solution)]
A reactor having a capacity of 2 L equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube was charged with 762 g of adipic acid, 49 g of maleic anhydride and 386 g of ethylene glycol, and at 150 ° C. and normal pressure while flowing nitrogen gas. The esterification reaction was carried out by stirring under the conditions of
When condensed water is no longer observed, add 0.1 g of tetrabutyl titanate, gradually reduce the pressure in the reaction system to 0.07 kPa, and gradually raise the temperature to 190 ° C. to continue the reaction. To obtain a polyester. The number average molecular weight of the obtained polyester was 2,000, and the iodine value was 12.7 gI / 100 g.
Subsequently, 74 g of the above polyester and 150 g of butyl acetate were charged into a 500 mL reactor equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube, and the temperature was raised to 110 ° C. while flowing nitrogen gas. , Stirred. Thereafter, a dissolved mixture of 75 g of methoxy PEG (polymerization degree 7) methacrylate and 1 g of benzoyl peroxide was dropped from the dropping funnel over 1 hour. After completion of the dropwise addition, the dispersion was heated to 130 ° C. and further reacted for 2 hours to obtain a dispersion stabilizer solution having a solid content of 50%. Hereinafter, this is referred to as “dispersion stabilizer solution (2)”.

<Example 1>
(1) First step:
A polyester diol having a number average molecular weight of 1,000 obtained from 1,4-BD and adipic acid, which is a polymer polyol, is added to a reactor having a capacity of 3 L equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube 255.3 g of PBA-1000), 255.3 g of polyester diol (PBEA-2600) having a number average molecular weight of 2,600 obtained from ethylene glycol, 1,4-BD and adipic acid, 1,6-HD and isophthalic acid Of polyester diol (HiP-1000) having a number average molecular weight of 1,000 obtained from the above, and polyester diol (HoP-1500) having a number average molecular weight of 1,500 obtained from 1,6-HD and orthophthalic acid. 2 g was mixed at 90 ° C.
Next, the mixture is cooled to 65 ° C., 13.9 g of dialkylamine , di-2-ethylhexylamine, is added and further mixed, and 139.3 g of hexamethylene diisocyanate (HDI) is added to the bismuth catalyst “Neostan U-600. And 0.050 g (manufactured by Nitto Kasei Co., Ltd.) was added and reacted at 65 ° C. for 15 minutes and then at 80 to 90 ° C. for 3 hours.
After confirming that the NCO content was 1.36% which is the designed value, an isocyanate group-containing prepolymer was obtained.

(2) Second step:
After the isocyanate group-containing prepolymer obtained in the first step is cooled to 60 ° C., 200 g of MEK and 42.9 g of dispersion stabilizer solution (1) are added and mixed uniformly to obtain an isocyanate group-containing prepolymer / dispersion. The agent mixture was prepared.
The amount of MEK is an amount corresponding to 20% with respect to the obtained isocyanate group-containing prepolymer. The amount of the dispersion stabilizer solution (1) is an amount corresponding to 3.0% with respect to the obtained isocyanate group-containing prepolymer.
Next, the total amount of the blend was adjusted to 60 ° C., and mixed and dispersed in 60 ° C. hot water (2353 g) for 2 minutes at a rotation speed of 8000 rpm using a homomixer (mechanical forced disperser) manufactured by Primix Co., Ltd. .
This mixed dispersion was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, and reacted at 60 ° C. for 10 hours while stirring.

  In this example, the ratio [(x1 + x2) / A] is 0.30 and the ratio (x1 / x2) is 15/85.

(2) Third step:
The solid content (polyurethane urea resin) is filtered off from the polyurethane urea resin dispersion obtained in the second step, and the additives (i) to (iv) shown below are added thereto. The mixture was transferred to a stirring vessel equipped with a stirrer, mixed with stirring at 80 ° C. for 2 hours, and then dried under reduced pressure until the internal pressure was lowered to a water content of less than 0.3%. After drying, 3.0 g of a dusting agent “MP1451” (manufactured by Soken Chemical Co., Ltd.) was added and mixed, and particles of 300 μm or more were classified and cut. Further, 7.0 g of a mixture of additives (v) and (vi) shown below (v / vi = 15/85) was added, and the mixture was stirred and mixed with a Henschel mixer at a rotational speed of 6000 rpm for 2 minutes. About 1000 g of a plastic polyurethaneurea resin was prepared. The obtained resin had a spherical shape and an angle of repose of 26 °.

〔Additive〕
(i) Antioxidant: “Irganox 245” (manufactured by Ciba Specialty Chemicals), added amount = 2.5 g.
(Ii) Ultraviolet absorber: “Tinubin 213” (manufactured by Ciba Specialty Chemicals), addition amount = 1.5 g.
(Iii) Light stabilizer: “Tinuvin 765” (manufactured by Ciba Specialty Chemicals), addition amount = 1.5 g.
(Iv) Internal mold release agent: “SH200-100,000 cs” (manufactured by Toray Dow Corning Co., Ltd.), addition amount = 2.0 g.
(V) Black pigment: carbon black dispersion pigment “PV-817” [mixture of carbon black as a powder pigment and calcium carbonate as a pigment dispersant in a ratio of 40/60] (manufactured by Sumika Color Co., Ltd.)
(Vi) White pigment: titanium oxide dispersion pigment “PV-7A1301” [mixture of titanium oxide as a powder pigment and calcium carbonate as a pigment dispersant in a ratio of 70/30] (manufactured by Sumika Color Co., Ltd.)

<Examples 2 to 9>
Each of the powdery thermoplastic polyurethane urea resins was prepared through the following first to third steps.

(1) First step:
In the same manner as in the first step of Example 1, an isocyanate group-containing prepolymer solution was prepared using a predetermined amount of polymer polyol, dialkylamine , HDI, and catalyst according to the formulations shown in Table 1 and Table 2 below.

(2) Second step:
After blending the isocyanate group-containing prepolymer obtained in the first step with MEK and the dispersion stabilizer solution (1) under the same conditions as in the second step of Example 1, the blend was placed in warm water at 60 ° C. The mixture was dispersed, then transferred to another reaction vessel, and reacted at 60 ° C. for 10 hours with stirring.
Tables 1 and 2 below also show the amounts of water and dispersion stabilizer used, and the ratio [(x1 + x2) / A] and ratio (x1 / x2) values.

(3) Third step:
The solid content (polyurethane urea resin) was filtered off from the polyurethane urea resin dispersion obtained in the second step, and the additives (i) to (vi) used in Example 1 were the same as in Example 1. About 1000 g of powdery thermoplastic polyurethane urea resin was prepared by adding and mixing by the method. The obtained resins were all spherical and had an angle of repose of 26 °.

In Table 1 and Table 2 below, the substances indicated by abbreviations are as follows.
* “PBA-1000”:
A polyester diol having a number average molecular weight of 1,000, obtained from 1,4-BD and adipic acid.
* “PBEA-2600”:
A polyester diol having a number average molecular weight of 2,600 obtained from 1,4-BD, ethylene glycol and adipic acid.
* “PHiP-1000”:
A polyester diol having a number average molecular weight of 1,000, obtained from 1,6-HD and isophthalic acid.
* “PHoP-1500”:
A polyester diol having a number average molecular weight of 1,500 obtained from 1,6-HD and orthophthalic acid.

* "U-600 (catalyst)":
Bismuth-based catalyst “Neostan U-600” (manufactured by Nitto Kasei Co., Ltd.).
* "MEK (organic solvent)":
"Methyl ethyl ketone" (manufactured by Kyowa Hakko Chemical Co., Ltd.).
* "PL-PB (plasticizer)":
A polyester plasticizer (manufactured by Nippon Polyurethane Industry Co., Ltd.) obtained from PEG-400 and benzoic acid.
* “D-2EHA (monofunctional active hydrogen compound)”:
“Di-2-ethylhexylamine” (manufactured by Guangei Chemical Co., Ltd.).

<Comparative Examples 1-2>
Each of the powdery thermoplastic polyurethane urea resins was prepared through the following first to third steps.

(1) First step:
In the same manner as in the first step of Example 1, according to the formulation shown in Table 1 below, a predetermined amount of polymer polyol, dialkylamine , HDI, catalyst, MEK, dispersion stabilizer solution (1) was used to prepare an isocyanate group-containing prepolymer. A polymer solution was prepared.

(2) Second step:
The isocyanate group-containing prepolymer solution obtained in the first step was dispersed in 60 ° C. warm water under the same conditions as in the second step of Example 1, and then transferred to another reaction vessel and stirred at 60 ° C. For 10 hours.
Table 1 shows the amounts of water and dispersion stabilizer used, and the ratio [(x1 + x2) / A] and ratio (x1 / x2) values.

(3) Third step:
The solid content (polyurethane urea resin) was filtered off from the polyurethane urea resin dispersion obtained in the second step, and the additives (i) to (vi) used in Example 1 were the same as in Example 1. About 1000 g of powdery thermoplastic polyurethane urea resin was prepared by adding and mixing by the method. The obtained resins were all spherical and had an angle of repose of 27 °.

In Comparative Example 1, the ratio [(x1 + x2) / A] is 0.20, and the ratio (x1 / x2) is 15/85. In Comparative Example 2, the ratio [(x1 + x2) / A] is 1.70, and the ratio (x1 / x2) is 15/85.
The comparative example 1 is an example in which the use ratio [(x1 + x2) / A] of the monofunctional active hydrogen group-containing compound is below the lower limit of the claims, and the comparative example 2 is an example in which the ratio exceeds the upper limit.

<Comparative Examples 3-4>
Each of the powdery thermoplastic polyurethane urea resins was prepared through the following first to third steps.

(1) First step:
In the same manner as in the first step of Example 1, an isocyanate group-containing prepolymer using a predetermined amount of polymer polyol, dialkylamine , HDI, catalyst, MEK, dispersion stabilizer solution (1) according to the formulation shown in Table 2 The solution was adjusted.

(2) Second step:
Under the same conditions as in the second step of Example 1, the isocyanate group-containing prepolymer solution obtained in the first step was dispersed in warm water at 60 ° C., then transferred to another reaction vessel, and stirred at 60 ° C. For 10 hours.
Table 2 shows the amounts of water and dispersion stabilizer used, and the values of the ratio [(x1 + x2) / A] and the ratio (x1 / x2).

(3) Third step:
The solid content (polyurethane urea resin) was filtered off from the polyurethane urea resin dispersion obtained in the second step, and the additives (i) to (vi) used in Example 1 were the same as in Example 1. About 1000 g of powdery thermoplastic polyurethane urea resin was prepared by adding and mixing by the method. The obtained resins were all spherical and had an angle of repose of 26 °.

In Comparative Example 3, the ratio [(x1 + x2) / A] is 0.90, and the ratio (x1 / x2) is 3/97. In Comparative Example 4, the ratio [(x1 + x2) / A] is 0.90, and the ratio (x1 / x2) is 40/60.
The comparative example 3 is an example in which the ratio (x1 / x2) is lower than the lower limit of the claims, and the comparative example 4 is an example in which the ratio is higher than the upper limit.

<Examples 10 to 17>
According to the prescription described in Table 3 below, each of the powdery thermoplastic polyurethane urea resins was prepared through the same first to third steps as in Example 1.

  Example 10 is an example using the dispersion stabilizer solution (2), and the other resin composition is the same as that of Example 3.

  Examples 11 to 12 are examples in which PL-PB (plasticizer) was used instead of MEK when adjusting the isocyanate group-containing prepolymer solution. The addition amount of PL-PB (plasticizer) is 10% and 25%, respectively, with respect to the resulting isocyanate group-containing prepolymer.

  Example 13 is an example in which the amount of the dispersion stabilizer solution (1) used in Example 3 was changed to 5%.

  Example 14 is a synthesis example in a solvent-free system that does not use MEK when preparing an isocyanate group-containing prepolymer solution. In addition, since the viscosity of the isocyanate group-containing prepolymer was high in the solventless system, the dispersion temperature in the second step was raised to 80 ° C. to cope with it.

  Examples 15-16 are the examples which increased / decreased the quantity of MEK used when adjusting an isocyanate group containing prepolymer solution with respect to Example 3. FIG. In Example 15, it is 10% with respect to the obtained isocyanate group-containing prepolymer, and in Example 16, it is 30%.

In Example 17, when the dispersion stabilizer solution (1) used in Example 3 was changed to the dispersion stabilizer solution (2) and the isocyanate group-containing prepolymer solution was further prepared, MEK and PL-PB (plastic This is an example in which an agent is used in combination.
The amount of the dispersion stabilizer solution (2) used is 5.0% with respect to the obtained isocyanate group-containing prepolymer, and the amount of MEK and PL-PB (plasticizer) is based on the obtained isocyanate group-containing prepolymer. On the other hand, it is 15%.

<Comparative Example 5>
According to the formulation described in Table 3, a powdered thermoplastic polyurethane urea resin was prepared through the same first to third steps as in Example 1.

  Comparative Example 5 is an example in which PL-PB (plasticizer) was used when adjusting the isocyanate group-containing prepolymer solution. The addition amount of PL-PB (plasticizer) is 35% with respect to the obtained isocyanate group-containing prepolymer, which is a use amount exceeding the preferred range of the present invention.

<Comparative Example 6>
According to the formulation described in Table 4, a powdered thermoplastic polyurethane urea resin was prepared through the following first to third steps.

(1) First step:
A reactor having a capacity of 3 L equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube was charged with PBA-1000: 254.2 g, PBEA-2600: 254.2 g, and PHiP-1000: 169 as in Example 1. 0.5 g, PHoP-1500: 169.5 g were mixed at 90 ° C.
The liquid temperature was cooled to 65 ° C., 13.8 g of dialkylamine di-2-ethylhexylamine was added and further mixed, and 138.7 g of hexamethylene diisocyanate (HDI) and a bismuth catalyst “Neostan U-600” ( Nitto Kasei Co., Ltd. (0.050 g) was added and reacted at 65 ° C. for 15 minutes and then at 80-90 ° C. for 3 hours.
The isocyanate content was 1.36%, which is the designed value, and it was confirmed that the reaction was complete, and an isocyanate group-containing prepolymer was obtained.
Next, after the isocyanate group-containing prepolymer was cooled to 60 ° C., 200 g of MEK and 42.9 g of the dispersion stabilizer solution (1) were added and mixed uniformly to prepare a prepolymer solution.
The amount of MEK is an amount corresponding to 20% with respect to the obtained isocyanate group-containing prepolymer. The amount of the dispersion stabilizer solution (1) is an amount corresponding to 3.0% with respect to the obtained isocyanate group-containing prepolymer.

(2) Second step:
18.8 g of hexamethylenediamine (hereinafter abbreviated as HDA) is mixed in 1000 g of water adjusted to 60 ° C. for 5 minutes using a homomixer (mechanical forced disperser) manufactured by PRIMIX Corporation for 5 minutes. HDA was dispersed.
Next, the isocyanate group-containing prepolymer solution obtained in the first step was adjusted to 60 ° C., and 1333 g of water adjusted to 60 ° C. (prepared in another container) using the same homomixer (mechanical forced disperser) as above. The mixture was mixed at a rotation speed of 8000 rpm for 10 minutes and dispersed in warm water at 60 ° C.
The HDA dispersion and the isocyanate group-containing prepolymer solution dispersion were mixed and reacted.
This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, and reacted at 70 ° C. for 10 hours with stirring.

    This Comparative Example 6 is a comparative example using HDA in the same number of moles as the water used as a chain extender in Example 1 (water reacting with isocyanate groups in the isocyanate group-containing prepolymer solution). When the number of moles of active hydrogen groups possessed (the number of moles that undergo urea reaction with an isocyanate group) is x2 ′, the ratio [(x1 + x2 ′) / A] is 0.30 and the ratio (x1 / x2 ′) is 15 / 85.

(3) Third step:
The solid content (polyurethane urea resin) was filtered off from the polyurethane urea resin dispersion obtained in the second step, and the additives (i) to (vi) used in Example 1 were the same as in Example 1. About 1000 g of powdery thermoplastic polyurethane urea resin was prepared by adding and mixing by the method. The obtained resins were all spherical and had an angle of repose of 38 °.

<Comparative Example 7>
According to the formulation described in Table 4, a powdered thermoplastic polyurethane urea resin was prepared through the following first to third steps.

<Production of MEA ketimine product of HDA>
The product water was removed out of the system while refluxing HDA and excess MEK (4-fold molar amount with respect to diamine) at 80 ° C. for 24 hours. Thereafter, unreacted MEK was removed under reduced pressure to obtain a MEK ketimine product of HDA.

(1) First step:
A reactor having a capacity of 3 L equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube was charged with PBA-1000: 254.2 g, PBEA-2600: 254.2 g, and PHiP-1000: 169 as in Example 1. 0.5 g, PHoP-1500: 169.5 g were mixed at 90 ° C.
The liquid temperature was cooled to 65 ° C., 13.8 g of dialkylamine di-2-ethylhexylamine was added and further mixed, and 138.7 g of hexamethylene diisocyanate (HDI) and a bismuth catalyst “Neostan U-600” ( Nitto Kasei Co., Ltd. (0.050 g) was added and reacted at 65 ° C. for 15 minutes and then at 80-90 ° C. for 3 hours.
The isocyanate content was 1.36%, which is the designed value, and it was confirmed that the reaction was complete, and an isocyanate group-containing prepolymer was obtained.
Next, after the isocyanate group-containing prepolymer was cooled to 60 ° C., 36.3 g of the HDA MEK ketiminate, 42.9 g of the dispersion stabilizer solution (1), and 177 g of MEK were added and mixed uniformly to obtain the isocyanate group-containing prepolymer. A polymer solution was prepared.
The amount of MEK is an amount corresponding to 20% with respect to the obtained isocyanate group-containing prepolymer, including those ketiminized. The amount of the dispersion stabilizer solution (1) is an amount corresponding to 3.0% with respect to the obtained isocyanate group-containing prepolymer.

(1) Second step:
The isocyanate group-containing prepolymer solution obtained in the first step is adjusted to 60 ° C. and mixed for 2 minutes at a rotation speed of 8000 rpm using a homomixer (mechanical forced disperser) manufactured by PRIMIX Co., Ltd. and adjusted to 60 ° C. The resulting product was dispersed in 2333 g of warm water.
This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, and reacted at 60 ° C. for 10 hours with stirring.

    This Comparative Example 7 is a comparative example using HDA MEK ketiminate in place of the water used as the chain extender in Example 1. Moreover, it is also a comparative example using the same mole number of HDA MEK ketiminate as HDA used as a chain extender in Comparative Example 6, and the number of moles of active hydrogen groups generated when the MEA ketiminate of HDA comes into contact with water ( If the number of moles of the urea group reacting with the isocyanate group is x2 ′ ′, the ratio [(x1 + x2 ′ ′) / A] is 0.30 and the ratio (x1 / x2 ′ ′) is 15/85.

(2) Third step:
The solid content (polyurethane urea resin) was filtered off from the polyurethane urea resin dispersion obtained in the second step, and the additives (i) to (vi) used in Example 1 were the same as in Example 1. About 1000 g of powdery thermoplastic polyurethane urea resin was prepared by adding and mixing by the method. Each of the obtained resins had a true spherical shape and an angle of repose of 37 °.

<Examples 18 to 20>
According to the prescription described in Table 5 below, each of powdery thermoplastic polyurethane urea resins was prepared through the same first to third steps as in Example 1.

Examples 18 to 20 are examples in which the values of the ratio [(x1 + x2) / A] and the ratio (x1 / x2) were set to the same values as in Example 3 and the type of dialkylamine was changed.
In Example 18, n-butanol (carbon number of hydrocarbon group: 4), in Example 19, n-octanol (carbon number of hydrocarbon group: 8), and in Example 20, lauryl alcohol (carbon number of hydrocarbon group: 12). ) Is used.

  Each of the obtained powdery thermoplastic polyurethane urea resins having a shape of about 1000 g had a true spherical shape and an angle of repose of 26 to 29 °.

<Comparative Examples 8 to 10>
According to the prescription described in Table 5 below, each of powdery thermoplastic polyurethane urea resins was prepared through the same first to third steps as in Example 1.

Comparative Examples 8 to 10 are examples in which the ratio [(x1 + x2) / A] and the ratio (x1 / x2) were set to the same values as in Example 3 and the type of dialkylamine was changed.
In Comparative Example 8, ditridecylamine (2 moles of hydrocarbon group having 13 carbon atoms) is used, in Comparative Example 9, ethanol (carbon number of hydrocarbon group is 2), and in Example 10, tetradecanol (carbon of hydrocarbon group is used). Equation 14) is used.

  Each of the obtained powdery thermoplastic polyurethane urea resins having a shape of about 1000 g had a true spherical shape and an angle of repose of 27 to 30 °.

<Evaluation of powdered thermoplastic polyurethane urea resin>
About each of the powdery thermoplastic polyurethane urea resin obtained by Examples 1-20 and Comparative Examples 1-10, it measured and evaluated about the following item. The results are shown in Tables 6 to 10 below.

(1) Molecular weight measurement:
According to GPC measurement, the ratio (peak area ratio in the measurement chart) of the hardly fusible substance (component with Mn of 500,000 or more), the number average molecular weight (Mn) and the weight average molecular weight (Mw) in the component excluding the hardly fusible substance Asked. The measurement conditions are as follows.
-Measuring instrument: "HLC-8120" (manufactured by Tosoh Corporation)
Column: “TSKgel Multipore HXL-M” (manufactured by Tosoh Corporation)
Particle size = 5 μm, size = 7.8 mm ID × 30 cm × 4 carriers ・ Carrier: Tetrahydrofuran (THF)
Detector: Parallax refraction Sample: 1% solution of THF / n-methylpyrrolidone = 2/1 Calibration curve: standard polystyrene

(2) Average particle size:
A cumulative percent value of 50% in the volume fraction particle size distribution curve measured with a laser particle size analyzer “Microtrack HRA” (manufactured by Nikkiso Co., Ltd.) was determined.

(3) Melt formability (leveling property):
Molded polyurethane resin is heated for 10 seconds in a mold heated to 230 ° C, unmelted powder is removed, left in an oven at 300 ° C for 45 seconds, and then cooled with water to form a 1mm thick molded sheet Was made. The molten state of the sheet thus obtained was visually observed and evaluated according to the following criteria.

(Evaluation criteria)
“◎”: No melting failure is observed.
“◯”: Some unsatisfactory melting failure is recognized.
“×”: Melting failure is considerably recognized.

(4) Melt formability (pinhole state):
The presence and extent of pinholes on the surface of the sheet obtained by (3) above were visually observed and evaluated according to the following criteria.

(Evaluation criteria)
“◎”: Pinholes are not allowed.
“◯”: Some pinholes are inconspicuous.
“X”: Pinholes are considerably recognized.

(5) Melt moldability (green strength expression when demolding):
The presence / absence and degree of deformation of the sheet obtained by (3) above at the time of demolding were visually observed and evaluated according to the following criteria.

(Evaluation criteria)
“◎”: Deformation is not recognized.
“◯”: Slight deformation is observed.
"X": Deformation is clearly recognized.

(6) Folding resistance of the molded product:
The sheet obtained by the above (3) is left for 30 seconds after demolding, held for 30 seconds in a state where it is bent 180 °, spread and left to stand for 24 hours, and then the bent portion is visually observed. Observed and evaluated according to the following criteria.

(Evaluation criteria)
“◎”: No creases are allowed.
“O”: Some creases are inconspicuous.
“×”: creases are clearly recognized.

(7) Abrasion resistance of molding surface:
About the sheet | seat obtained by said (3), 100 reciprocation tests were done on the following conditions using the reciprocating motion plane abrasion tester, the state of the sheet | seat surface was observed visually, and it evaluated according to the following reference | standard.

(conditions)
・ Reciprocating speed = 40 times / min ・ Friction: 30 mm × 12 mm
・ Load = 29.4N
・ Wear material: Stack of 5 white cotton kanakin No.3

“◎”: No damage was observed.
“◯”: Some damage is inconspicuous.
"X": Damage is noticeable.

(8) Mechanical properties of the molded product:
About the sheet | seat obtained by said (3), the tension test and the tear test were done according to JISK6251-6252, and the tensile strength, the breaking, and the tear strength were measured.

(9) Blooming resistance of the molded product:
The sheet obtained by the above (3) was immersed in water at 50 ° C. for 48 hours, and then dried, and the presence / absence and degree of blooming on the surface were visually observed and evaluated according to the following criteria.

(Evaluation criteria)
“◎”: Blooming is not allowed.
“◯”: Blooming is slightly observed.
“X”: Blooming is noticeable.

(10): Residual amine In each Example and Comparative Example, after the filtration in the third step was completed, whether or not amine remained in the filtrate water was confirmed using the following method.
(I) Weigh accurately 10 g of the filtrate.
(Ii) Add a small amount of indicator to the filtrate and titrate with 0.01N hydrochloric acid.

(Evaluation criteria)
“◎”: No amine residue was observed (less than 0.05 mol / L).
“X”: Amine residue is observed (0.05 mol / L or more).

(11): Residual isocyanate In each example and comparative example, after filtration in the third step was finished, 10 g of separated crystals (wet cake) was dissolved in 100 g of N, N-dimethylformamide at 90 ° C. The presence or absence of isocyanate groups to be confirmed was confirmed using FT-IR. In addition, since an isocyanate group shows absorption specifically in the vicinity of 2200 cm ⁻¹ , it can be easily discriminated.

(Evaluation criteria)
“◎”: No isocyanate group remains.
“X”: Remaining isocyanate group is observed.

(12): Blocking resistance (hygroscopicity)
In each Example and Comparative Example, the degree of powder blocking (aggregation solidification) under high-temperature and high-humidity conditions was confirmed for each of the obtained powdered thermoplastic polyurethane urea resins.
(I) 500 g of a powdered thermoplastic polyurethane urea resin is charged into a 1000 ml stainless steel cup.
(Ii) Leave in an environment of 50 ° C./95% RH for 48 hours.
(Iii) Remove the sample from the constant temperature and humidity chamber and leave it in an environment of 25 ° C / 50% RH for 24 hours.
(Iv) The fluidity of the powdered thermoplastic polyurethane urea resin was evaluated by the following indices.

(Evaluation criteria)
“◎”: The fluidity of the powder is not changed from that before the test.
“◯”: The fluidity of the powder is slightly lower than before the test.
“X”: The powder is agglomerated and solidified in the stainless steel container, and the fluidity of the powder is lost.

<Supplementary explanation of each comparative example>

<Comparative Example 1>
In Comparative Example 1, since the ratio (x1 + x2) / A (= 0.2) is less than the claimed range, the crease resistance and the wear resistance are below the allowable limit, which is not practical. I understand.

<Comparative example 2>
In Comparative Example 2, since the ratio (x1 + x2) / A (= 1.7) exceeds the claimed range, the meltability of the obtained powdered polyurethane urea resin is below the allowable limit, and is not practical. I understand.

<Comparative Example 3>
In Comparative Example 3, since the ratio x1 / x2 (= 3/97) is lower than the claimed range, the number average molecular weight of the obtained powdered polyurethane urea resin is excessive, and as a result, the meltability is below the allowable limit. Therefore, it is not practical.

<Comparative example 4>
In Comparative Example 4, since the ratio x1 / x2 (= 40/60) exceeds the claimed range, the number average molecular weight of the obtained powdered polyurethaneurea resin becomes too small, and the crease resistance and wear resistance are reduced. Is less than acceptable and is not practical.

<Comparative Example 5>
In Comparative Example 5, the amount of PL-PB (plasticizer) added when producing the isocyanate group-containing prepolymer solution exceeds the preferred range. For this reason, the strength of the resin is greatly reduced, and as a result, the crease resistance and the wear resistance are below the allowable limit, which is not practical.

<Comparative Example 6>
Comparative Example 6 is a comparative example in which the water that reacts with the isocyanate group-containing prepolymer in Example 1 was replaced with HDA having the same number of moles. Since HDA is highly reactive with isocyanate groups, it is difficult to knead it into a prepolymer. For this purpose, first prepare a suspension in which HDA is forcibly dispersed in water as a dispersion medium, then prepare a suspension in which the isocyanate group-containing prepolymer solution is dispersed in water in a separate container, and stir both A polyurethane urea resin dispersion was produced by mixing.
In Comparative Example 6, since the reaction of HDA and the isocyanate group-containing prepolymer proceeds non-uniformly, a high-quality powdered thermoplastic polyurethane urea resin cannot be obtained. Specifically, it can be estimated that the chain extension reaction with HDA proceeds only on the surface of the isocyanate group-containing prepolymer particle, and the chain extension reaction hardly proceeds inside the particle. In order to support this, when the amount of amine in the “filtrate” taken out in the solid-liquid separation step of the third step was measured, it was clearly confirmed that HDA remained. Further, the “filter crystal” was dissolved in N, N-dimethylformamide and measured by FT-IR, and it was confirmed that an isocyanate group remained in the resin. From the fact that HDA remains in the dispersion medium and isocyanate groups remain in the particles, it is clear that the reaction is not completed as designed.
Furthermore, due to residual isocyanate groups in the resin, the obtained powdered thermoplastic polyurethaneurea resin can be easily altered in a high temperature and high humidity environment, and it can be pointed out that there is a risk of causing blocking failure.

<Comparative Example 7>
Comparative Example 7 is a comparative example in which the water that reacts with the isocyanate group-containing prepolymer in Example 1 was replaced with the same mole number of HDA MEK ketiminate. Since the MEK ketiminate of HDA does not react with the isocyanate group as it is, it can be kneaded into the prepolymer. For this reason, when preparing an isocyanate group-containing prepolymer solution, a MEK ketimine product of HDA was kneaded in advance and then dispersed / reacted in water to produce a polyurethane urea resin dispersion.
In Comparative Example 7, HDA remains as in Comparative Example 6, and it is clear that the reaction is not completed as designed. Further, if even a small amount of HDA remains on the surface of the separated crystal, the quality of the obtained powdered thermoplastic polyurethane urea resin is remarkably deteriorated, so that it is necessary to sufficiently wash (rinse) the separated crystal.

<Comparative Example 8>
The value of (x1 + x2) / A (= 0.9) and the value of x1 / x2 (= 15/85) in Comparative Example 8 are the same as those in Example 3, but the di-alkylamine used in Example 3 as a dialkylamine was used. In this example, di-tridecylamine is used instead of 2-ethylhexylamine. Di-tridecylamine is a secondary amine to which 2 moles of a hydrocarbon group having 13 carbon atoms is added, and the carbon number exceeds the upper limit of the claims of the present invention. For this reason, it turns out that the blooming resistance of the molded article shape | molded using the obtained powdery polyurethane urea resin has deteriorated remarkably, and is not practical.

<Comparative Example 9>
The value of (x1 + x2) / A (= 0.9) and the value of x1 / x2 (= 15/85) in Comparative Example 9 are the same as those in Example 3, but the di-alkylamine used in Example 3 was used as the dialkylamine. In this example, ethanol (carbon number 2 of hydrocarbon group) is used instead of 2-ethylhexylamine, and the carbon number exceeds the lower limit of the claims of the present invention. This is an example that is not suitable as a monofunctional active hydrogen compound because of its low boiling point. In other words, since the ethanol that should react with the isocyanate group in the first step evaporates and stays in the gas phase in the reaction vessel, the reaction rate of the isocyanate group-containing prepolymer varies from lot to lot. The number average molecular weight of the obtained powdered polyurethane urea resin cannot be stably controlled (see * 1 in Table 10).

<Comparative Example 10>
The value of (x1 + x2) / A (= 0.9) and the value of x1 / x2 (= 15/85) in Comparative Example 10 are the same as in Example 3, but the di-alkylamine used in Example 3 as a dialkylamine In this example, tetradecanol (carbon number 14 of hydrocarbon group) is used in place of 2-ethylhexylamine, and the carbon number exceeds the upper limit of the claims of the present invention. For this reason, it turns out that the blooming resistance of the molded article shape | molded using the obtained powdery polyurethane urea resin has deteriorated remarkably, and is not practical.

The powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention can stably control the molecular weight, and balances the meltability and mechanical strength / abrasion resistance at the time of thermoforming at a high level. Is possible.
In addition, since the reaction is completely completed, there is no fear of alteration or blocking, and there are no remaining amine compounds or isocyanate groups that adversely affect the human body.
In particular, the powdered thermoplastic polyurethane urea resin obtained by the production method of the present invention is suitable as a powder material for slush molding. The slush molded product made of the polyurethane urea resin is particularly suitable as an automobile interior material, and is also useful as a skin material for indoor furniture such as a sofa.

Claims (6)

A method for producing a powdered thermoplastic polyurethane urea resin, comprising the following first to third steps,
In the first step, A is the number of moles of active hydrogen groups of the polymer polyol that reacts with the organic polyisocyanate, and x1 is the number of moles of dialkylamine having a hydrocarbon group of 4 to 12 carbon atoms that reacts with part of the isocyanate groups. In the second step, when the number of moles of active hydrogen groups having water that reacts with the remainder of the isocyanate group is x2, the ratio [(x1 + x2) / A] is 0.3 to 1.5, and the ratio (x1 / x2) is 5 / 95-35 / 65, The manufacturing method of the powdery thermoplastic polyurethane urea resin characterized by the above-mentioned.
First step: A step of preparing an isocyanate group-containing prepolymer by reacting a polymer polyol and a dialkylamine having a hydrocarbon group having 4 to 12 carbon atoms with an organic polyisocyanate.
Second step: After the isocyanate group-containing prepolymer is dispersed in water in the presence of a dispersion stabilizer, the remainder of the isocyanate group of the isocyanate group-containing prepolymer is reacted with the active hydrogen group of water to form a polyurethane urea resin. A step of preparing a dispersion liquid.
Third step: A step of preparing a powdery thermoplastic polyurethane urea resin by separating and drying the polyurethane urea resin from the obtained dispersion. 2. The production of a powdery thermoplastic polyurethane urea resin according to claim 1, wherein the isocyanate group-containing prepolymer contains an organic solvent capable of substantially dissolving the isocyanate group-containing prepolymer and / or a plasticizer. Method. The powder according to claim 1 or 2, wherein the ratio [(x1 + x2) / A] is 0.3 to 1.2, and the ratio (x1 / x2) is 5/95 to 20/80. Process for producing a thermoplastic polyurethaneurea resin. The powder according to claim 1 or 2, wherein the ratio [(x1 + x2) / A] is 0.75 to 1.5, and the ratio (x1 / x2) is 10/90 to 35/65. Process for producing a thermoplastic polyurethaneurea resin. The method for producing a powdered thermoplastic polyurethane urea resin according to any one of claims 1 to 4, wherein the organic polyisocyanate used in the first step is hexamethylene diisocyanate. The method for producing a powdered thermoplastic polyurethane urea resin according to any one of claims 1 to 5, wherein a powdery thermoplastic polyurethane urea resin for slush molding is produced.