JP2992984B2 - Method for producing thermoplastic polyurethane resin for extrusion molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a thermoplastic polyurethane resin for extrusion molding . More specifically,
The present invention relates to a method for producing a thermoplastic polyurethane resin for extrusion molding, in which a projection-like projection, a so-called fish eye, hardly occurs on the surface of a molded product during extrusion molding.

[0002]

2. Description of the Related Art Thermoplastic polyurethane resins generally use long-chain diols, short-chain diols and isocyanates as raw material components. Although the actual production is carried out by various methods, in the case of a thermoplastic polyurethane resin for extrusion molding, the raw materials are mixed and then continuously reacted in a twin-screw extruder or a belt or kneaded like a kneader. A method of performing a batch reaction in an apparatus is generally used.

When producing a thermoplastic polyurethane resin for extrusion molding with these facilities, the most important thing is a portion formed by a bond between a short-chain diol and an organic diisocyanate in a polyurethane molecule. The purpose is to distribute the hard segments evenly. If the dispersion of the hard segments is not uniform, a homogeneous resin cannot be formed, and a portion having an excessively high hard segment content appears as fish eyes on the surface of the extruded product. When fish eyes are generated in this way, the appearance of the molded product is poor, the physical properties are deteriorated, and the like, and it is often difficult to use the product as an industrial product.

[0004] In the past, several studies on the improvement of fish eyes have been reported. They include methods for improving the mixing state of raw material components by changing production equipment (for example, JP-A-56-5244) and methods for mechanically controlling the fluctuation of the melt viscosity of the obtained polyurethane (for example, Japanese Patent Application Laid-Open No. Sho 62-15219), however, these methods do not fundamentally solve fish eyes and are not the best methods from the viewpoint of cost.

A method using an ester group-containing diol for the purpose of forming a solution by dissolving a thermoplastic polyurethane resin in an organic solvent is disclosed in Japanese Patent Laid-Open No. 60-115616.
Issue. In this method, the diol containing an ester group is used in a high proportion of 30 to 100 mol% of the total chain extender, so that the resin obtained by this method has excellent solubility in an organic solvent, but is extruded. When used as a resin for molding or injection molding, the excellent heat resistance and solvent resistance inherent to thermoplastic polyurethane resins cannot be obtained.

[0006]

DISCLOSURE OF THE INVENTION The present inventors used existing production equipment and did not impair the excellent heat resistance and solvent resistance of the conventional thermoplastic polyurethane resin, and did not damage the fish during extrusion. As a result of intensive studies on a method for fundamentally solving the eye generation by chemical means, they found that the problem can be solved by using a special third component as a compatibilizing agent, and reached the present invention.

[0007]

[Means for Solving the Problems] That is, the present invention provides:
A method for producing a thermoplastic polyurethane resin for extrusion molding , comprising: an organic diisocyanate (A) having a molecular weight of 500 to 5;
When using a long-chain diol (B), a short-chain diol (C) having a molecular weight of 60 to 500, and a compatibilizer (D), the short-chain diol (C) contains no ester group.
The compatibilizer (D) is composed of glycol and hydroxy
1: 1 (molar ratio) reaction with a group-containing monocarboxylic acid
Or triol and hydroxy-free monocal
1: 1 (molar ratio) reaction product with boric acid, molecular weight 1
30 to 500 ester group-containing diols, (B)
Thermoplastic resin for extrusion molding , wherein the molar ratio of + (C) to (D) is 15/85 ≧ (D) / {(B) + (C)} ≧ 0.1 / 99.9 The present invention relates to a method for producing a polyurethane resin.

[0008] According to the present invention, the presence of ester <br/> Le group-containing diol as a compatibilizer, by producing a thermoplastic polyurethane resin, an improved dispersion state of the hard segment, in homogeneous fisheye Less extrusion
It has become possible to provide a thermoplastic polyurethane resin for use .

The organic diisocyanate used in the present invention includes tolylene diisocyanate, diphenylmethane diisocyanate, 2,2'-dimethyl-4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, and tetramethylene. Diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 4,4'-diphenylene diisocyanate, 4,4'-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, p-xylylene diisocyanate, m-xylylene Diisocyanate, 1,3-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane,
4,4'-diisocyanate dicyclohexane, isophorone diisocyanate, and the like. These can be used alone or as a mixture of two or more.

The long-chain diol used in the present invention includes polyester diol and polycarbonate diol having a molecular weight of 500 to 5,000. Examples of the carboxylic acid component of the polyester diol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and maleic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and orthophthalic acid; Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be exemplified. The glycol component of the polyester diol includes ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-butenediol, 1,5-pentanediol, methyl-1,5- Pentanediol, 1,6-
Hexanediol, neopentyl glycol, methyl-
1,8-octanediol, 1,9-nonanediol,
Diethylene glycol, cyclohexane dimethanol,
Polyethylene glycol, polypropylene glycol,
And polytetramethylene ether glycol. These carboxylic acids and glycols
It can be used alone or as a mixture of two or more. Other polyester diols include ε-caprolactone, β
Lactone-based polyester diols obtained by ring-opening polymerization of lactones such as -methyl-γ-valerolactone. Further, as the polycarbonate diol, a general formula Wherein R is ethylene glycol
, Diethylene glycol, propylene glycol,
Glycol residues such as 1,6-hexanediol . These long-chain diols can be used alone or as a mixture of two or more .

The short chain diol containing no ester group used in the present invention is a diol having a molecular weight of 60 to 500. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-butenediol, 1,5-pentanediol, methyl-1,5-pentanediol, 1,6-hexane Diol, neopentyl glycol, methyl-
1,8-octanediol, 1,9-nonanediol,
Diethylene glycol, cyclohexane dimethanol,
Polyethylene glycol, polypropylene glycol,
And polytetramethylene ether glycol. Among them, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3 - methyl-1,5-pentanediol,
Aliphatic diols such as 1,6-hexanediol are preferred.

[0012] compatibilizing agent used in the present invention, the first glycol and hydroxy group-containing monocarboxylic acid: 1 (molar ratio)
It is a reaction product or a 1: 1 (molar ratio) reaction product of a triol and a hydroxy-free monocarboxylic acid, and has an ester group-containing diol having a molecular weight of 130 to 500.
It is a rule. In this case, the glycol may have 2 carbon atoms
Aliphatic glycols such as ethylene glycol, propylene glycol, 1,4-butanediol,
1,3-butanediol, 1,5-pentanediol,
Methyl-1,5-pentanediol, 1,6-hexanediol, methyl-1,8-octanediol, 1,9
Alicyclic glycols having 6 to 10 carbon atoms such as nonanediol, for example, 1,4-cyclohexanediol, 1,3
-An aromatic glycol having 6 to 10 carbon atoms, such as cyclohexanediol and cyclohexanedimethanol, for example,
Examples thereof include dihydroxybenzene and bishydroxyethoxybenzene. Further, these glycols may contain an ester bond or an ether bond in a main chain or a side chain. Examples of the hydroxyl group-containing monocarboxylic acid include a hydroxyl group-containing aliphatic monocarboxylic acid having 2 to 10 carbon atoms, such as hydroxyacetic acid, hydroxypropionic acid, methylhydroxypropionic acid, dimethylhydroxypropionic acid, hydroxybutanoic acid, and methylhydroxybutane. Acid, dimethylhydroxybutanoic acid, etc., a hydroxyl group-containing alicyclic monocarboxylic acid having 7 to 10 carbon atoms, for example, hydroxycyclohexylacetic acid, hydroxycyclohexylbutanoic acid, a hydroxyl group-containing aromatic monocarboxylic acid having 7 to 10 carbon atoms For example, salicylic acid and the like can be mentioned.

The hydroxyl group-containing monocarboxylic acid may have an ester bond or an ether bond in the main chain or side chain. Glycerin,
And trimethylolpropane. Examples of the monocarboxylic acid include aliphatic monocarboxylic acids having 2 to 20 carbon atoms, such as acetic acid , propionic acid, caproic acid, lauric acid, stearic acid, acrylic acid, crotonic acid, and oleic acid. An aromatic monocarboxylic acid, for example, an alicyclic monocarboxylic acid having 7 to 20 carbon atoms, such as benzoic acid, may be used.

The compatibilizer (D) of the present invention is a long-chain diol.
If the (B) and ester groups containing no short chain diol (C)
The molar ratio is 15/85 ≧ (D) / {(B) + (C)} ≧ 0.1 / 99.9. Below the lower limit of this range, it is difficult to obtain the effect as a compatibilizer, and above the upper limit ,
The strength, heat resistance, solvent resistance, and adhesion between resins occur, and the properties originally required of the thermoplastic polyurethane resin for extrusion molding cannot be obtained.

As a method for producing the thermoplastic polyurethane resin for extrusion molding, a one-shot method in which all components are mixed and reacted simultaneously, or a method in which a long-chain diol and an organic diisocyanate are first reacted to form an NCO-terminated prepolymer, After that, there is a prepolymer method in which a short-chain diol is added to complete the reaction. The present invention can be produced by either the one-shot method or the prepolymer method, but the effect is particularly remarkable in the one-shot method. As a method for producing a thermoplastic polyurethane resin for extrusion molding, there are a solventless reaction in which the raw material is melted or partially non-molten, and a method in which the raw material is dissolved in a solvent. Has a remarkable effect in a solventless reaction.

[0016]

According to the present invention, by manufacturing a thermoplastic polyurethane resin for extrusion molding in the presence of an ester group-containing diol, the dispersion state of the hard segments is improved, and a thermoplastic polyurethane resin having a uniform and low fisheye is obtained. It has become possible to provide conventional equipment without any changes. Extrusion molding obtained according to the invention
Use polyurethane resin, there is provided a tube, belt, fiber, stable product in a wide range of fields, such as.

[0017]

Next, the present invention will be described in detail with reference to examples. "Parts" and "%" in Examples and Comparative Examples are
"Parts by weight" and "% by weight" are shown, respectively.

Example 1 100 parts of a long-chain diol (B ₁ ), 14 parts of 1,4-butanediol, and 3 parts of neopentyl glycol-2,2-dimethyl-3-hydroxypropionate were mixed after melting. A uniform glycol component was obtained. This glycol component and 55 parts of molten diphenylmethane diisocyanate were stirred and mixed, fed from a hopper of a twin-screw extruder whose temperature was adjusted to about 200 ° C., kneaded and simultaneously resinified to obtain a thermoplastic polyurethane resin for extrusion molding . . Using this resin, a belt was made with a single-screw extruder. The surface of the belt was observed with a microscope to evaluate fish eyes. Further, a sheet was prepared by injection molding, and the heat resistance, solvent resistance and general physical properties were evaluated using this sheet.

EXAMPLES 2-5, COMPARATIVE EXAMPLES 1-5 A thermoplastic polyurethane resin was obtained by the same apparatus and method as in Example 1 with a composition having a molar ratio shown in Table 1. Similarly, a sample was prepared and evaluated.

When the surface of the extruded belt was visually observed and observed with a microscope, almost no fish eyes were contained, and the surface of the molded product was much smoother than a belt obtained from a usual thermoplastic polyurethane resin.

Table 1 shows the raw material components, and Table 2 shows the fisheye evaluation and resin properties. In the comparative example, no fisheye due to an abnormal reaction was observed on the belt surface in the case where no compatibilizing agent was added, and in the case where the compatibilizing agent was added to the upper limit or more, the solvent resistance, heat resistance, and physical properties were high. The result was worse.

[0022]

[Table 1]

Notes on Table 1 Long-chain diol (B ₁ ): adipic acid / 1,4-butanediol = 28/19 (molar ratio) Molecular weight 2000 Long-chain diol (B ₂ ): adipic acid / 1,6-hexane Diol = 28/25 (molar ratio) Molecular weight 2000 Long-chain diol (B ₃ ): diethyl carbonate / 1,6-hexanediol = 13/14 (molar ratio) Molecular weight 2000 MDI: 4,4-diphenylmethane diisocyanate Molecular weight 250 HDI: 1,6-hexamethylene diisocyanate molecular weight 168 1,4-BG: 1,4-butanediol molecular weight 90 ESG: neopentyl glycol-2,2-dimethyl-3-hydroxypropionic acid ester molecular weight 204 BBE: 1,4- Butanediol-4-hydroxybutanoate Molecular weight 176 BPE: 1,4-butanediol-3-hydroxypropionate ester Molecular weight 162

[0024]

[Table 2]

Evaluation method in Table 2 1) Tensile strength at break: According to JIS K7311. 2) Elongation at break: according to JIS K7311. 3) Solvent resistance: A sample sheet (injection molding) of 120 mm × 120 mm × 2 mm was added to MEK for 25 times.
C. for 6 hours, and the volume change rate was measured. ◎: good (change rate from normal value is 25% or less) ○: normal (change rate from normal value is about 25 to 50%) △: slightly inferior (change rate from normal value is 50% or more) ×: poor (form 4) Heat resistance: The sample sheet was placed in a gear oven at 120 ° C. for 7 days, and then the tensile strength was measured.良 い: good (change rate from normal value is 10% or less) ○: normal (change rate from normal value is 10 to 20% or less) △: slightly inferior (change rate from normal value is 20% or more) ×: poor (form Not stop)

Continuation of front page (56) References JP-A-60-115616 (JP, A) JP-A-2-170816 (JP, A) JP-A-56-47416 (JP, A) JP-A-52-23156 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 18/00-18/87 C08L 75/00-75/16

Claims (1)

(57) [Claims] 1. A method for producing a thermoplastic polyurethane resin for extrusion molding , comprising: an organic diisocyanate (A), a long-chain diol (B) having a molecular weight of 500 to 5000, and a molecular weight of 60.
When using the short-chain diol (C) and the compatibilizer (D) of ~ 500, the short-chain diol (C) does not contain an ester group.
Yes , the compatibilizer (D) is composed of glycol and a hydroxy group-containing
A 1: 1 (molar ratio) reaction product with a carboxylic acid, or
Of triol with monocarboxylic acid containing no hydroxy group
A molecular weight of 130 to 50, which is a 1: 1 (molar ratio) reaction product
0: an ester group-containing diol having a molar ratio of (B) + (C) to (D) of 15/85 ≧ (D) / {(B) + (C)} ≧ 0.1 / 99.9. A method for producing a thermoplastic polyurethane resin for extrusion molding , characterized in that: