JPH03715A - Polyurethane resin - Google Patents

Abstract

PURPOSE:To obtain the title resin with a high softening point, without decompsn. in melt molding and with excellent heat resistance by reacting a macropolyol, a polyisocyanate and a specified chain extender. CONSTITUTION:A macropolyol (e.g. polycaprolactone polyol), a polyisocyanate (e.g. diphenylmethane diisocyanate) and a chain extender at least part of which is p-xylene glycol are reacted together.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to polyurethane resins, and more specifically, an object of the present invention is to provide thermoplastic polyurethane resins that have excellent thermal properties such as heat resistance.

(Prior art and its problems) Polyurethane resins have traditionally been widely used as binders for various coating agents, paints, inks, films, molded bodies, etc., and polyurethane resins suitable for each use have been proposed. has been done.

These polyurethane resins are basically obtained by reacting macropolyols, polyisocyanates, and chain extenders, and polyurethane resins with various physical properties are provided depending on the types and combinations of these components. There is.

However, conventional polyurethane resins have insufficient heat resistance for applications that require excellent thermal properties, such as injection molding and extrusion molding, and they tend to discolor or foam due to thermal decomposition. There is a problem that

A common method for improving the heat resistance of polyurethane resins is to use diamine as a chain extender and incorporate urea bonds into the polyurethane resin, but in this case, although the softening point improves, Applications where the softening point and decomposition point are close to each other, melting and processing polyurethane resin,
For example, there is a problem in that it is difficult to use in injection molding or extrusion molding.

Another known method is to use a chain extender having an aromatic ring such as 1,4-bis(2-hydroxyethoxy)benzene or bis(hydroxyethyl)terephthalate; however, in this method, Compared to the case of using general glycols such as 1,4-butanediol, propylene glycol, 1,6-hexanediol, etc., the softening point is slightly improved, but it is insufficient.

Therefore, an object of the present invention is to provide a thermoplastic polyurethane resin having a high softening point and excellent heat resistance that does not decompose even during melt molding.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a thermoplastic polyurethane resin obtained by reacting a macropolyol, a polyisocyanate, and a chain extender, characterized in that at least a part of the chain extender is paraxylene glycol. be.

(Function) By using paraxylene glycol as at least a part of the chain extender during the production of polyurethane resin, it has a high softening point and excellent heat resistance that does not decompose even during melt molding. A thermoplastic polyurethane resin is provided.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments of the present invention.

The polyurethane resin of the present invention is characterized in that when a macropolyol, a polyisocyanate, and a chain extender are reacted to obtain a polyurethane resin, paraxylene glycol is used as at least a part of the chain extender.

The macropolyol used in the present invention is a conventionally known macropolyol for polyurethane, especially a diol, and any conventionally known macropolyol can be used. For example, preferred ones include polyethylene adipate and polyethylene propylene with a molecular weight of 500 to 3,000. Adipate, polyethylene butylene adipate, polydiethylene adipate, polybutylene adipate, polyethylene succinate polybutylene succinate, polyethylene sebacate polybutylene sebacate, polytetramethylene ether glycol, poly〇-caprolactone diol, polyhexamethylene adipate, Examples include polycarbonate polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, polyethylene polyols, polypropylene glycols, and polyols containing an appropriate amount of polyoxyethylene chains in the above polyols.

Particularly preferred macropolyols in the present invention are polybutylene adipate, polyethylene butylene adipate, polyε-caprolactone, polytetramethyl ether glycol, and polycarbonate polyols having a molecular weight of 1.000 to 2,000.

Further, as the polyisocyanate, any conventionally known polyisocyanate can be used, but for example, 4,4-diphenylmethane diisocyanate (MDI) is preferred.
, hydrogenated MDI, isophorone diisocyanate, 1.3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 2.4-tolylene diisocyanate, 2.6-tolydine diisocyanate, 1.5-naphthalene diisocyanate, m-phenylene Examples include diisocyanate, p-phenylene diisocyanate, toridine diisocyanate, and urethane prepolymers obtained by reacting these polyisocyanates with low molecular weight polyols or polyamines to form terminal isocyanates.

In the present invention, polyisocyanates particularly suitable for improving heat resistance are 4,4'-diphenylmethane diisocyanate (MDI) and toridine diisocyanate.

The chain extender used in the present invention and which mainly characterizes the present invention is paraxylene glycol, which is represented by the following structural formula.

The para-xylene glycol can be prepared by halogenating the methyl groups of para-xylene and hydrolyzing it, or can be obtained from the market and used.

The above-mentioned paraxylene glycol can be used alone as a chain extender, and can also be used in combination with a conventionally known chain extender. Preferred examples of known chain extenders include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexane dimetatool m-xylylene glycol Hydrogenated bisphenol A 1.4-bis(2-hydroxyethoxy)benzene, bis(hydroxyethyl)terephthalate, 1.2-propylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, isophoronediamine , m-xylylenediamine, hydrazine, water, etc.

The polyurethane resin of the present invention made of the above-mentioned raw materials can be easily obtained by conventionally known manufacturing methods, such as a batch reaction method of each component, a prepolymer method using a prepolymer, and the like.

These polyurethane resins may be prepared without a solvent or in an organic solvent.

As for the reaction conditions, for example, a small amount of a reaction catalyst such as dibutyltin laurate, stannath octoate, or tertiary amine is used, and each component is mixed, for example,
A polyurethane resin having a desired molecular weight can be obtained by reacting at a temperature of about 0 to 200° C. for several hours to more than ten hours.

In the present invention, the reaction ratio of the macropolyol, polyisocyanate, and paraxylene glycol is such that the equivalent ratio of hydroxyl groups to isocyanate of all components is OH/NGO=
It is preferable to react at an equivalent ratio of 0.90 to 1.30 (7), particularly preferably to an equivalent ratio of 1.0 to 1.10.

If the OH/N CO ratio is out of the above range, the molecular weight of the resulting polyurethane resin will be low (and heat resistance will be insufficient), and as a result of residual functional groups remaining after the reaction, thermoplasticity will decrease, which is undesirable.

The ratio of macropolyol to paraxylene glycol is also important, and the molecular weight of macropolyol is 50%.
0 to 3,000, macropolyol/paraxylene glycol = 97/3 to 30/70, especially 9
The weight ratio is 515 to 40/60, and the molar ratio is 60
/40 to 10/90, preferably 30/70 to lO
A range of 90 to 90 is preferable. If the amount of paraxylene glycol used is less than the above range, the effect of improving the heat resistance of the resulting polyurethane resin will be low; on the other hand, if the amount of paraxylene glycol used is too large, the elasticity and low temperature of the resulting polyurethane resin will be reduced. This is not preferable because the properties such as properties become insufficient. Also, preferred ones have a molecular weight of 30,000 to 30
The most preferable one is a molecular weight of 50,000 to 20,000.
It belongs to millions of people.

In particular, in the present invention, the softening point can be set to 230°C or higher, particularly 250°C to 300°C, by selecting preferable macropolyols and polyisocyanates as described above and appropriate amounts of chain extenders. The present invention provides a polyurethane resin which can be melt-molded without thermal decomposition at temperatures above the softening point.

(Effect) The polyurethane resin of the present invention as described above can be used as a chain extender such as a conventionally known general chain extender or a chain extender for improving heat resistance, such as 1,4-bis(2-hydroxy In addition to having significantly superior heat resistance compared to polyurethane resins obtained using such materials as ethoxy)benzene and bis(hydroxyethyl) terephthalate, it also has superior properties such as chemical resistance and compression set. Therefore, applications that require melting and molding at high temperatures, such as packing, moving materials, etc.
It is suitable for applications such as injection molded products and extrusion molded products such as belts, heat and pressure resistant tubes, sports shoe nails and heel tops, and applications such as printing rolls and paint tubes that require resistance to chemicals such as ink.

It is presumed that the above effects are due to the fact that the chain extender used in the present invention is an aromatic glycol at discrete positions and that the distance between the two hydroxyl groups is shorter than in the conventional chain extender. Ru.

(Example) Next, the present invention will be described in more detail by giving examples and comparative examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight.

Example 1 Polycaprolactone polyol (molecular weight 2.000) 8
00 parts and 165 parts of paraxylene glycol (
Weight ratio = 83/17)L, this is heated to 100 to 120℃
Warm it up.

On the other hand, 411 parts of diphenylmethane diisocyanate was added to 8
After heating to 0 to 120°C and rapidly mixing both, they were placed in a Teflon container and further heated at 120"C for 24 hours to complete the reaction, and then crushed to obtain the polyurethane resin of the present invention. .

Examples 2 to 10 The polyurethane system of the present invention was prepared in the same manner as in Example 1, except that the weight ratio of paraxylene glycol, which is a chain extender, and polycaprolactone in Example 1 was changed as shown in Table 1 below. Resin was obtained.

(Left below) Comparative Example 1 Comparison was made in the same manner as in Example 1, except that 114-butanediol was used in an equimolar ratio instead of para-xylene glycol as the chain extender in Example 1. An example polyurethane resin was obtained.

Comparative Example 2 Polyurethane of Comparative Example was prepared in the same manner as in Example 1 except that 1,4-bis(2-hydroxyethoxy)benzene was used in an equimolar ratio instead of paraxylene glycol as the chain extender in Example 1. A system resin was obtained.

Comparative Example 3 A polyurethane resin of a comparative example was obtained in the same manner as in Example 1 except that bis(hydroxyethyl) terephthalate was used in an equimolar ratio instead of paraxylene glycol as the chain extender in Example 1.

Example 11 A polyurethane resin of the present invention was obtained in the same manner as in Example 1 except that a polycarbonate polyol (molecular weight 2,000) was used in an equimolar ratio instead of the macropolyol in Example 1.

Example 12 Example 1 except that toridine diisocyanate was used in an equimolar ratio instead of the diisocyanate in Example 1.
A polyurethane resin of the present invention was obtained in the same manner as above.

Example 13 A polyurethane of the present invention was produced in the same manner as in Example 1, except that paraxylene glycol and 1,4-butanediol were used in a weight ratio of 3.5:1 instead of the chain extender in Example 1. When various physical properties of the polyurethane resins of the above Examples and Comparative Examples were measured, the results shown in Table 2 below were obtained.

In addition, even if polybutylene adipate, polyethylene butylene adipate, polyC caprolactone, or polytetramethyl ether glycol having a molecular weight of 1,000 to 2,000 is used as the macropolyol in the above examples, similarly excellent heat resistance etc. can be obtained. A polyurethane resin of the present invention having the following properties was obtained.

(Left below) Sudden 1-≦L-j豫[-1≧-122≧ (Continued) *1: A load of 100g is hung on a No. 3 dumbbell (thickness 2mm) and heated at a temperature increase rate of 2℃/min. The softening point is when the dumbbell suddenly stretches *2: JIS K6
Processing conditions = 80° C. x 18 hours *3: Solvent resistance was tested for Example 1 and Comparative Examples 1 to 3 by immersing a 2 mm thick test piece in each solvent for 24 hours according to 301.

×: Dissolution Δ: Swelling O = No change.

Claims (4)

[Claims] (1) A polyurethane resin obtained by reacting a macropolyol, a polyisocyanate, and a chain extender, characterized in that at least a part of the chain extender is paraxylene glycol. (2) The polyurethane resin according to claim 1, wherein the weight ratio of macropolyol/paraxylene glycol in the resin is in the range of 97/3 to 30/70. (3) The polyurethane resin according to claim 1, wherein the polyisocyanate is diphenylmethane diisocyanate or toridine diisocyanate. (4) The polyurethane resin according to claim 1, which has a softening point of 230°C or higher.