JP2000248034A - Polyurethane-based resin composition for abrasive material and foam from the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition high in safety and productivity in its molding process, capable of producing molded products with high abrasion resistance as urethane foams of uniform microcellular structure. SOLUTION: This polyurethane-based resin composition comprises A-liquid: an NCO-terminated urethane prepolymer prepared by reaction between diphenylmethane diisocyanate singly or its mixture with polyphenyl polymethylene polyisocyanate and a polyol 500-4,000 in number-average molecular weight, and B-liquid: comprising a short-chain diol, a foaming agent, a >=7C aliphatic polyamine-based catalyst, and, as necessary a polyol 500-4,000 in number-average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyurethane resin composition for an abrasive. More specifically, the present invention relates to a resin composition which can be molded at room temperature or relatively low temperature, has excellent safety during operation, and has excellent physical properties such as abrasion resistance and is excellent as a material for an abrasive.

[0002]

2. Description of the Related Art Conventionally, as a polishing material using a polymer foam, a polishing pad using a foamed polyurethane is preferably used because of its excellent abrasion resistance. As such a polyurethane foam for a polishing pad, JP-A-2-23
No. 2173 discloses 3,3′-dichloro-4,4′-.
A curing agent composed of diaminodiphenylmethane (MOCA), water as a foaming agent, triethylenediamine (trade name: Dabco, manufactured by Sankyo Air Products Co., Ltd.) as a catalyst, and a modified silicone oil, and a tri-dispersion of 250 μm epoxy resin powder. Range isocyanate (TDI)
/ Polytetramethylene glycol (PTMG) prepolymer (manufactured by Mitsui Toatsu Chemicals, Inc., trade name: Hyprene L-
315).

[0003] However, the above-mentioned urethane prepolymer obtained by adding MOCA and water has a limited reaction time due to a high reaction rate, and has a low workability when producing a thin product or a large molded product. There is a problem. Also,
Due to the high viscosity of the prepolymer and the high melting point of MOCA and the like, it is necessary to raise the temperature of the raw material to around 100 ° C. Further, the cell structure of the obtained urethane foam tends to be coarse, and it is difficult to obtain a foam having a microcell structure. In addition, TDI monomers in raw materials fall under Class 2 of the specified chemical substances and cause bronchial sighs, eczema, etc., and amines such as MOCA have the danger of carcinogenicity. It is becoming a problem. On the other hand, as a method for producing a high-density polyurethane foam (microcellular elastomer) used for shoe soles and the like, a foamed blue juran method is known. However, such NCO-terminated urethane prepolymers using naphthalenediisocyanate (NDI) as a raw material are expensive and have insufficient thermal stability.

[0004]

As described above, the conventional abrasive materials have various points to be improved. In recent years, however, the abrasive materials have been used for silicon wafers and liquid crystal glass. As developments continue, further improved materials are required. The present invention has been made in view of the above circumstances, its purpose is to improve the storage stability of urethane prepolymer, reaction rate, and workability, can be used at room temperature or relatively low temperature, safety,
An object of the present invention is to provide a polyurethane-based resin composition for an abrasive excellent in productivity and abrasion resistance, and to provide a foam having a microcell structure using the resin composition.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that by using an aliphatic polyamine catalyst having 7 or more carbon atoms, TDI is not used as a raw material. In both cases, the present inventors have found that the resin composition is excellent in safety and productivity, and that the obtained molded product is a foam having a good abrasion resistance and a uniform microcell structure, and has reached the present invention. That is, the gist of the present invention is to provide an NCO-terminated urethane prepolymer (solution A) obtained by reacting diphenylmethane diisocyanate alone or a mixture thereof with a polyphenylpolymethylene polyisocyanate and a polyol having a number average molecular weight of 500 to 4000. When,
A short-chain diol, a blowing agent, an aliphatic polyamine-based catalyst having 7 or more carbon atoms, and if necessary, a number average molecular weight of 500 to 4
000 polyol (liquid B).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. (1) Liquid A The prepolymer having a terminal NCO group (hereinafter abbreviated as “prepolymer”) used in the present invention is diphenylmethane diisocyanate (M
DI) or a mixture thereof with polyphenylpolymethylene polyisocyanate (polymeric MDI), and a urethane prepolymer obtained by reacting a polyol having a number average molecular weight of 500 to 4000 as a glycol component.

The MDI used in the present invention includes 4,4′-diphenylmethane diisocyanate,
2,2′- and 2,4′-diphenylmethane diisocyanate isomer mixtures, and carbodiimide-modified diphenylmethane diisocyanate. It is also possible to use a polymeric MDI if necessary. Normally, polymeric MDI has an NCO content of 25 to
Those having 35% and a viscosity of 2500 cps / 25 ° C. or less are used. Further, other diisocyanate compounds can be used in combination as long as the effects of the present invention are not impaired. Other diisocyanate compounds include 4,4 ′ dicyclohexylmethane diisocyanate (hereinafter H ₁₂ MD
I), isophorone diisocyanate (hereinafter IPDI),
1,5-naphthalenediisocyanate (hereinafter NDI),
Hexamethylene diisocyanate (hereinafter HMDI) and the like.

The number average molecular weight used in the present invention is 5
Examples of the polyols of 00 to 4000 include polyoxypropylene glycol, polytetramethylene glycol (hereinafter, PTMG), polycaprolactone glycol, polyester glycols obtained by a dehydration condensation reaction of a low molecular weight glycol and a dibasic acid (for example, 1,4-butane). Polyester glycol obtained from a diol and adipic acid). In particular, by using PTMG, it is possible to give a polyurethane elastomer cast product excellent in abrasion resistance and water resistance which cannot be obtained with other polyether polyols and polyester polyols. These polyols can be used alone or in combination of two or more.

A more preferable range of the number average molecular weight of the polyol is 650 to 3000. Here, the molecular weight is a value calculated from the terminal hydroxyl group. As a method for producing the liquid A, first, MDI or a polymer MDI
And PTMG in a stream of dry nitrogen at 20-90 ° C
For about 2 to 6 hours under stirring. At this time, a stabilizer can be added to the liquid A as needed. As the stabilizer, butyl acid phosphate,
Examples thereof include acid phosphates such as 2-ethylhexyl acid phosphate and isodecyl acid phosphate, and phosphites such as triphenyl phosphite, tridecyl phosphite and dibutylhydrodiene phosphite.

(2) Curing Agent (Solution B) The curing agent comprises a short-chain diol, a foaming agent, an aliphatic amine-based catalyst and, if necessary, a polyol having a number average molecular weight of 500 to 4000. Here, the short-chain diol used in the present invention usually has a number average molecular weight of 30.
0 or less, and 1,4-butanediol or 1,4-butanediol
A mixture of 4-butanediol and another short-chain diol is preferably used. Other short-chain diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexane. Diol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-1,3-hexane glycol, 2,2,4-trimethyl-1,3-pentanediol, 3,3-dimethylolheptane Aliphatic diols such as 1,9-nonanediol, 2-methyl-1,8-octanediol, bishydroxyethoxybenzene,
Aromatic diols such as bishydroxyethyl terephthalate and bisphenol A are used. When increasing the crosslink density, triols such as trimethylolpropane and glycerin can be used in combination. Water is typically used as the foaming agent, but an organic foaming agent such as azobisisobutyronitrile can also be used.

The number average molecular weight used in the present invention is 5
Examples of the polyols of 00 to 4000 include polyoxypropylene glycol, polytetramethylene glycol (hereinafter, PTMG), polycaprolactone glycol, polyester glycols obtained by a dehydration condensation reaction of a low molecular weight glycol and a dibasic acid (for example, 1,4-butane). Polyester glycol obtained from a diol and adipic acid). In particular, by using PTMG, it is possible to give a polyurethane elastomer cast product excellent in abrasion resistance and water resistance which cannot be obtained with other polyether polyols and polyester polyols. These polyols can be used alone or in combination of two or more.

The preferred range of the number average molecular weight of the polyol is 650 to 3000. Here, the molecular weight is a value calculated from the terminal hydroxyl group. PTMG is
For example, it can be produced by ring-opening polymerization of tetrahydrofuran as described in JP-A-61-162522. In the present invention, as a catalyst,
For the purpose of foaming the resin, an aliphatic polyamine compound having 7 or more carbon atoms is used. Specific compounds include, for example, N, N, N ′, N ′,-tetramethyl-1,3-butanediamine, N, N, N ′, N ″,
N "-pentamethyldiethylenetriamine, N, N-dimethylcyclohexylamine, N-methyldicyclohexylamine, N, N, N ', N'-tetramethylpropylenediamine, N, N, N', N'-tetramethylhexamethylene Diamine; bis [2- (N, N-dialkylamino) alkyl] ether, for example, bis [2-
(N, N-dimethylamino) ethyl] ether, bis [2- (N, N-dimethylamino) -1-methylethyl] ether, 2- (N, N-dimethylamino) ethyl-2- (N, N -Dimethylamino) -1-methylethyl ether and the like.

[0013] In addition, another urethane-forming catalyst may be used in combination to shorten the demolding time within a range not to impair the effects of the present invention. Specifically, for example, trialkylamines such as trimethylamine, triethylamine, dimethyldodecylamine, N-alkylmorpholine (for example, N-methylmorpholine, N-ethylmorpholine, B, B′-dimorpholinodiethylether), N ,
N-dimethylethanolamine, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU) and salts thereof, heterocyclic amines such as 1,4-dimethylpiperazine, amine compounds such as triethylenediamine, or Organic metal salts such as organic tin compounds and metal salts are exemplified. Organotin compounds are tin (II) or tin (IV) compounds,

[0014] Tin (II) salts, trialkyltin oxide, dialkyltin oxide, dialkyltin dihalide and the like can be mentioned. The organic group in the organic portion of these compounds is typically a hydrocarbon group containing from 1 to 8 carbon atoms. For example, dibutyltin dilaurate, dibutyltin diacetate, diethyltin diacetate, dihexyltin diacetate, di-2-ethylhexyltin oxide, dioctyltin oxide, tin octoate (I
I), tin (II) oleate, or mixtures thereof can be used. The organometallic and metal salts used in polyurethane chemistry are typically represented by VIII of the Periodic Table.
Group, IB, IIB and IVA metals (eg, tin,
(Lead, iron or mercury) or metal ions. In addition, bismuth, titanium, antimony, uranium, cadmium, cobalt, thorium, aluminum, zinc, nickel, molybdenum, vanadium, copper, manganese, and zirconium are suitable for use in the present invention.

From the viewpoint of shortening the demolding time of the urethane foam, it is particularly preferable to use an amine compound such as triethylenediamine among the above. The amount of the catalyst to be added in the present invention is usually 3 to 50000 ppm by weight, preferably 5 to 5 ppm by weight in the total amount of the solution A and the solution B.
20000 ppm by weight. If the amount is too small, the time required for the molded article to be released from the mold becomes longer, and the obtained foam has a coarse cell structure, which tends to make it difficult to obtain a microcell structure. If the amount is too large, the pot life (cream time) after mixing the reaction components (Solution A and Solution B)
Tend to be too short. If necessary, additives such as solid particles such as a surfactant, a pigment, a plasticizer, a waterproofing agent, an antioxidant, an ultraviolet absorber, and a light stabilizer can be added to the liquid B.

As the surfactant used here, an ordinary silicon-based surfactant can be used. Pigments include carbon black, titanium oxide, red iron oxide, graphite,
Phthalocyanine-based organic pigments and the like, and plasticizers include esters such as dibutyl phthalate and dioctyl phthalate. The solid particles include various inorganic solid particles such as cerium oxide, titanium oxide, aluminum oxide, barium carbide, glass powder, glass fiber, diatomaceous earth, rouge, calcium carbide, diamond, and carbon, or epoxy resin. And finely pulverized products such as unsaturated polyester resins, melamine resins and silicone resins.

(3) Method of mixing solution A and solution B The method for preparing the polyurethane resin composition of the present invention can be carried out by a usual method, for example, a one-shot method, a semi-prepolymer method, a prepolymer method. And the like. A
The compounding ratio of the liquid and the liquid B is such that the equivalent ratio of NCO group / OH group is usually 0.90 to 1.20, preferably 0.9
The range is 8 to 1.10. If this value is too small, the physical properties of the molded article, for example, the curing properties tend to decrease.
Further, the temperature of the solution at the time of mixing the solution A and the solution B is determined in consideration of the viscosity and the reactivity, but is usually preferably in the range of room temperature to 60 ° C. When casting the polyurethane resin composition of the present invention using a mold, the temperature of the mold is preferably from room temperature to about 100 ° C. If the temperature is too low, poor curing occurs and the demolding time is prolonged. If it is too high, problems such as coloring due to thermal deterioration are likely to occur. The urethane foam obtained by casting the polyurethane-based resin composition of the present invention can be sliced to form a 0.3 to 2 mm sheet, usually as a polishing pad.

[0018]

EXAMPLES Specific examples of the present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. In the following examples, “parts” and “%” represent parts by weight and% by weight, respectively, unless otherwise specified. Production Examples 1 to 3 (Production of Liquid A) MDI, polymeric MDI and PTMG in the number shown in Table 1 were dropped into a 1-liter glass flask and charged so that the reaction temperature did not exceed 70 ° C, and mixed. After the preparation of the polyol has been completed, at 70 ° C.
The reaction was carried out for a period of time to obtain solutions A to 1 to 3. Table 1 shows the measurement results of the NCO group content and the viscosity.

Here, PTMG1000 and 2000
(Mitsubishi Chemical Corporation) has a number average molecular weight of 99
9 and 1944. -Measurement method of NCO group content The measurement method of the NCO group content was measured according to JIS K1603.・ Measurement method of viscosity The viscosity was measured by E-type viscometer (Tokyo Keiki Co., Ltd.
(VISCONIC EHD-R type), and measured with a standard rotor (1 量 34 ′) in a sample volume of 1.5 ml.

Production Example 4 (Production of Liquid B) Liquid B was prepared by mixing at the mixing ratio shown in Table-2. As a result of confirming the compatibility of the obtained curing agent (liquid B), there was no occurrence of separation or the like, and the result was good. Examples 1, 3 and 4 Molded articles were produced using the liquid A obtained in Production Examples 1 to 3 and the liquid B obtained in Production Example 4 under the blending recipe and conditions shown in Table 3. . That is, the A liquid and the B liquid are set to a predetermined temperature, a release agent is applied in advance, and the inside of the heated mold (0.2 m
A liquid obtained by mixing the liquid A and the liquid B for 5 seconds with a handmix (stirring speed of 2800 rpm) into the mixture (× 0.2 mx 20 mm thick) was injected and cured to obtain a molded product. Subsequently, in order to complete the reaction, curing was performed in an oven at 100 ° C. for 10 hours.
The obtained molded article was aged for 7 days (23 ° C., 60% RH), and then sliced by machining to form a sheet having a thickness of 1 mm. The evaluation results of the obtained polyurethane resin composition and molded article are shown in Tables 3 and 4.

Example 2 Discharge rate of the liquid A obtained in the production example 1 and the liquid B obtained in the production example 3 by a low-pressure casting machine (manufactured by M & K Co., using a gear pump, a foaming machine for mixing with a mixing rotor). 1
It was poured into a mold (1 m × 1 m × 20 mm thick) at 0 kg / min, cured and molded in the same manner as in Example 1 to obtain a sheet-like molded product.

Example 5, Comparative Examples 1-2 TDI / PTMG prepolymer (Mitsui Toatsu Chemical Co., Ltd.)
And trade name: Prepolymer Hyprene L-315, an aqueous solution containing triethylenediamine (trade name: Dabco, manufactured by Sankyo Air Products Co., Ltd.) as a catalyst and a surfactant were added, and the mixture was uniformly mixed for 3 seconds. , MOCA was added, and a liquid mixed for 5 seconds at a stirring speed of 2800 rpm was poured into a mold (0.2 mx 0.2 mx 20 mm thick),
The composition was cured and molded in the same manner as in Example 1 to obtain a sheet-like molded product. As is clear from Tables 3 and 4, the polyurethane compositions of the examples are superior to those of the comparative examples in terms of workability and the resulting molded article has a microcell structure, and is excellent in abrasion resistance. ing.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

As described above, the polyurethane resin composition of the present invention comprises:
Since TDI and aromatic amines are not used, they are excellent in environmental hygiene and also excellent in safety at work. Furthermore, since it can be molded at room temperature or relatively low temperature, it is excellent in productivity and the obtained foam has excellent physical properties.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuo Shoji 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 4J034 BA08 CA04 CB03 CC08 DB04 DC50 DE04 DF01 DF11 DF12 DF16 DF20 DG04 DG05 DG08 HA01 HA02 HA06 HA07 HA13 HC12 HC13 HC17 HC22 HC61 HC64 HC65 HC67 HC71 JA42 KA01 KC17 KD02 KD11 KD12 MA01 MA03 NA01 NA03 QB16 QC01 RA19

Claims (3)

[Claims] 1. An NCO-terminated urethane prepolymer (solution A) obtained by reacting diphenylmethane diisocyanate alone or a mixture thereof with polyphenylpolymethylene polyisocyanate and a polyol having a number average molecular weight of 500 to 4000, A polyurethane resin for an abrasive, comprising a short-chain diol, a foaming agent, an aliphatic polyamine catalyst having 7 or more carbon atoms, and a polyol having a number average molecular weight of 500 to 4000 (solution B) as required. Composition. 2. The polyurethane resin composition for an abrasive according to claim 1, wherein the polyol (Solution A) is polytetramethylene glycol. 3. A polyurethane foam obtained by molding and curing the polyurethane resin composition for an abrasive according to claim 1 or 2.