JPH02163160A - Molded polyurethane product - Google Patents

Abstract

PURPOSE:To obtain a molded polyurethane product improved in discoloration resistance of a metallic coating film by forming a coating film containing aluminum powder on the surface of the molded polyurethane product containing a specific compound as a discoloration inhibitor blended therein. CONSTITUTION:A molded polyurethane product, having a metallic coating film and obtained by coating the surface of (A) the molded polyurethane product prepared by blending a polyisocyanate with a polyol, a tertiary amine catalyst, a crosslinking agent and, as necessary, a foaming agent, etc., and further 0.2-2wt.%, preferably 0.3-1.5wt.% compound expressed by formula I or II (n is 1-3; R is alkyl or phenyl which may have a substituent group) (e.g. trimethyl phosphate or methyl benzenesulfonate) and molding the resultant blend with (B) a coating containing 1-5wt.% aluminum powder (e.g. two-pack type polyester urethane), baking and curing the resultant film.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polyurethane molded product having a coating film containing aluminum powder (metallic coating film) formed on the surface thereof, and particularly relates to a polyurethane molded product having a coating film containing aluminum powder (metallic coating film) formed on the surface. This relates to a polyurethane molded product with improved discoloration resistance.

Polyurethane molded products with a coating film formed on their surfaces are used for automotive parts, electronic and electrical equipment parts, etc., depending on their physical properties, and in recent years they have been used for automotive bumpers, air, air, etc.
Applications are progressing to automotive exterior parts such as spoilers, fender doors and panels, and electronic and electrical equipment parts such as housings for computers and air conditioners.

[Traditional technique]

Polyurethane molded articles are usually produced by introducing a reaction mixture of polyisocyanate, polyol, crosslinking agent and additives into a sealable mold in the presence of a tertiary amine catalyst.

Polyurethane molded products used as parts for automobiles or electronic and electrical equipment are usually coated on their surfaces for design purposes and to improve weather resistance.

[Problem to be solved by the invention]

However, conventional polyurethane molded products that have a coating film containing aluminum powder formed on their surfaces are exposed to high humidity environments,
When exposed to water, the tertiary material in polyurethane moldings
The drawback was that the aluminum powder in the coating film was corroded by the action of the amine (catalyst for the urethanization reaction) and water, resulting in discoloration of the coating film.

[Means to solve the problem]

The present inventor has arrived at the present invention as a result of intensive studies on improving the discoloration resistance of polyurethane molded products formed by forming a metallic coating film on the surface.

That is, the present invention involves molding a foamed or non-foamed polyurethane resin by reacting it in a mold in the presence of a polyisocyanate, a polyol, a tertiary amine catalyst, and optionally a blowing agent and other additives, and producing a molded product thereof. A polyurethane molded product characterized in that a compound represented by the following general formula (1) or (2) is blended as a discoloration preventive agent when producing a polyurethane molded product with a coating film containing aluminum powder formed on the surface of the polyurethane molded product. be.

(C)l:10) 1IPR1-1゜・・・・・・・・・−・・−−・−−１・−・(1)
CHffO-5-R-1・・・・・・・・・・・・・・・
...(2) (in the general formula, 1≦n≦3, and R
represents an alkyl group or a phenyl group which may have a substituent. ) As a compound represented by such general formula (1),
For example, trimethyl phosphate, dimethyl methylphosphonate,
Examples include dimethyl phenylphosphonate, dimethyl tolylphosphonate, methyl dimethylphosphinate, and methyl diphenylphosphinate.

Examples of the compound represented by the general formula (2) include methyl benzenesulfonate, methyl p-)luenesulfonate, and methyl ethanesulfonate.

These discoloration inhibitors may be used alone, or
A mixture thereof may also be used. The amount of discoloration inhibitor used in the present invention is usually 0.2 to 2% by weight, preferably 0.3 to 1.5% by weight, based on the polyurethane molded article described below.

The polyisocyanate used in the present invention includes:
Those conventionally used in polyurethane production can be used. Such polyisocyanates include aromatic polyisocyanates such as 2,4- and/or 2,6-tolylene diisocyanate (TDI), crude T
DI, 2.4'- and/or 4.4'-diphenylmethane diisocyanate (MDI), crude MDI, etc.), aliphatic polyisocyanates (e.g. hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc.), aromatic fats Examples include group isocyanates (for example, xylylene diisocyanate, etc.), modified products thereof (modified products containing a urethane group, a carbodiimide group, a uretonimine group, an isocyanurate group, an oxazolidone group, etc.), and mixtures of two or more of these.

As the polyol used in the present invention, those conventionally used in polyurethane production can be used. Examples of such polyols include polyether polyols, polyester polyols, and polymer polyols. These polyols are 1
It usually has 2 to 8 hydroxyl groups in its molecule, and its concentration is about 20 to 500 mgKOH/g.

The crosslinking agent used in the present invention includes low molecular weight diols (e.g., ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
1,4-butanediol, 1,6-hexanediol, etc.), alkanolamines (e.g. monoethanolamine, jetanolamine, triethanolamine, motuprobanolamine, tripropaturamine, etc.),
Aliphatic polyamines (e.g., ethylenediamine, trimethylenediamine, tetramethylenediamine, diethylenetriamine, etc.), aromatic polyamines (e.g., phenylenediamine, tolylenediamine, diethyltolylenediamine, diphenylmethanediamine, methylenebis(0)
-chloroaniline) and mixtures of two or more thereof.

The amount of crosslinking agent used is usually 5% based on the weight of the polyol.
-40%, preferably 10-300-30%.

As the catalyst for the polyurethanization reaction used in the present invention, a tertiary amine is used, and a tin-based catalyst or the like may also be used in combination.

Examples of tertiary amine catalysts include triethylamine, triethylenediamine, 2-methyltriethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylhexamethylene Diamine, N, N, N', N'-
Tetramethylpropylene diamine, N, N, N',
Using N'N'pentamethyldiethylenetriamine, trimethylaminoethylpiperazine, N,N'-dimethylcyclohexylamine, N,N'-dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, and mixtures thereof Can be done.

The amount of tertiary amine catalyst used is usually 0.1 to 5% by weight based on the total weight of polyol and crosslinker.

As the tin-based catalyst, diptyltin dilaurate, stannous octylate, etc. can be used, and the amount used is usually 0.0 O based on the total weight of the polyol and crosslinking agent.
It is 5 to 1%.

Further, in the present invention, a blowing agent (for example, trichloromonofluoromethane, dichloromethane, water, etc.) can be used if necessary during the production of polyurethane.

The amount of blowing agent used is based on the total weight of polyol and crosslinking agent, in the case of trichloromonofluoromethane or dichloromethane, it is 1 to 10 weight percent, and in the case of water, it is 0.1 to 2 weight percent.
Weight%.

In the present invention, when molding polyurethane, NGO index (equivalent ratio of NCO group/active hydrogen atom-containing group
00) is usually 80-120, preferably 95-108.

The paint for forming the coating film containing aluminum powder used in the present invention usually consists of a curing resin containing 1 to 5% by weight of aluminum powder, and the curing resin is two-component polyester urethane, two-component polyester urethane, two-component polyester urethane, two-component polyester urethane, Liquid type acrylic urethane, melamine-cured urethane polyester, etc. can be used. Specifically, elastomer paint R257/R230 (
Nippon B Chemical 0x), Sofre Sox 1400 (Kansai Paint Kiki), Planit U160 (Dainippon Paint)
), Planiso) M130 (Dainippon Paint Co., Ltd. 01) and the like can be used.

Such a paint is applied to the surface of the polyurethane molded article by spraying or the like, and then cured by baking to form a coating film.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. In the examples, "parts" indicate "parts by weight."

The raw materials used in the Examples and Comparative Examples are as follows.

(1) Anti-discoloration agent TMP Trimethyl diphosphate DMMP: Dimethyl methylphosponate DMPP: Dimethyl phenylphosphonate MBS: Methyl benzenesulfonate (2) Catalyst DBTDL Nidibutyltin dilaurate DABCO33
LV: 33% dipropylene glycol (3) of I-lyethylenediamine Polyol A: A trifunctional polyol with a weight of 28 mg and Ol/g, which is obtained by adding 4,700 parts of propylene oxide to 92 parts of glycerin, and then 1,200 parts of ethylene oxide.

(41 Crosslinking agent: Ethylene glycol (5) Isonate 1 4 3 L: Carbodiimide modified MDI (NGO content 28.3%) (6) Paint Paint A: Two-component polyester urethane paint Aluminum powder content 4 % Paint B Knee molded melamine cured acrylic paint Aluminum powder content 4% Examples 1 to 9, Comparative Examples 1.2 A polyol consisting of a polyol, a crosslinking agent and a catalyst was molded according to the recipe listed in Table 1 under the following molding conditions. The premix and isocyanate were each placed in the raw material tank of a high-pressure foaming machine, and the reaction mixture obtained by 1ii thrust mixing with a mixing head was heated to a thickness of 3.0 mm x width of 550 mm.
A polyurethane molded article was molded by injecting it into a temperature-adjustable closed mold with a length of 600 mm. The anti-discoloration agent was added to the polyol premix in Examples 1 and 2, and to the isocyanate in Examples 3 to 9 to obtain molded articles.

〔Molding condition〕

High-pressure foaming machine HD500 (High-pressure foaming machine manufactured by Admiral) Discharge speed: 500 g/sec Discharge pressure: 15
0~170kg/cJ Raw material temperature: 2℃ above the raw material Mold temperature: 70±2℃ The resulting polyurethane molded product has a width of 70 mm x length of 150 mm.
A sample of Example 1 was prepared, washed for 1 minute in a trichloroethane vacuum tank, and dried at room temperature for 10 minutes.
9 and Comparative Example 1.2 were lined up at the same time, the paint A or paint B was sprayed with an air spray gun, and after setting for about 10 minutes, the paint film was baked by heating to obtain a painted sample. In addition, when using paint B, it is heated at 100℃ for 30 minutes, and when using paint B, it is heated for 12 minutes.
Baking was performed at 0°C for 30 minutes.

The color fastness of the obtained paint sample was 4.
After immersing in ion-exchanged water adjusted to 0°C for 240 hours, the degree of discoloration of the paint film before and after immersion is determined by measuring the Hunter color difference ΔE (Lab) using a colorimeter and visual judgment. It was evaluated by The evaluation results of color fastness are shown in Table 1.

〔Effect of the invention〕

A polyurethane molded article containing the specific compound of the present invention has excellent discoloration resistance of a metallic coating film even when a coating film containing aluminum powder is formed.

applicant

Claims (1)

[Claims] (1) In a polyurethane molded product formed by forming a coating film containing aluminum powder on the surface of a polyurethane molded product produced using a tertiary amine as a catalyst, the polyurethane molded product contains the following general formula (1) or (2). ) A polyurethane molded product characterized by blending the compound represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼……………………(
1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼……………………(
2) (In the general formula, 1≦n≦3, and R represents an alkyl group or a phenyl group that may have a substituent.)