JPH01204921A - Manufacture of molded product of elastic elastomer - Google Patents

Abstract

PURPOSE:To obtain an elastic polyurethane elastomer that is not brittle at the time of release from the mold and shows suitable flow properties, by the reaction injection molding of a polyisocyanate using a diaminodiphenyl ether as a chain extending agent. CONSTITUTION:A urethane group-containing polyisocyanate (A) is produced by the reaction of a polyisocyanate, preferably 4,4'-diphenylmethane diisocyanate, with a polypropylene having a molecular weight of below 700. A composition comprising the urethane group-containing polyisocyanate (A), an active hydrogen compound (B) having a molecular weight of 1,000-18,000, such as a polyol, a diaminodiphenyl ether (C) of the given formula (wherein R1 and R2 are each H, 1-4C alkyl, alkoxy or Cl with the proviso that R1 and R2 are not simultaneously an alkyl group) as a chain extending agent, and auxiliaries (D) such as catalysts, foaming agents, etc. is subjected to reaction injection molding in a hermetically sealed mold to produce the title product of a polyurethane or a polyurea.

Description

Detailed Description of the Invention (Industrial Application Field) Relatively high-density polyurethane or polyurea-based elastic elastomer moldings produced by reaction injection molding technology have excellent physical properties, moldability, and appearance, and can be used in a wide range of applications. used in the field. Specific application examples include automobile plate materials, sports and leisure goods, housing for office equipment, furniture,
A wide variety of agricultural equipment, etc. The most commonly used of these are automobile bumpers, fascias, fenders, doors, side moldings and the like.

(Prior Art) It is known to mold non-foamed polyurethanes (polyureas), fiber-reinforced elastomers, or microcellular polyurethane elastomers by reaction injection molding by polyaddition of isocyanates and active hydrogen-containing compounds.

The raw materials for these polyurethanes or polyureas are usually polyisocyanates, active hydrogen-containing compounds in terms of polymers (polyether polyols, polyester polyols, polyether polyamines, etc.), and low molecular weight active hydrogen-containing compounds as chain extenders ( alkanediols, aromatic polyamines, etc.) and, if necessary, catalysts, blowing agents, additives, and fibrous inorganic compounds (0-reaction injection molding method).
Reaction Injection Molding
(hereinafter abbreviated as RIM) is a method in which an isocyanate and an active hydrogen-containing compound are collidingly mixed under pressure (often under high pressure) using a mixing injection machine, this mixture is filled into a mold, and after curing, the molded product is taken out. A detailed description of the reaction injection molding method can be found in the following document: "Reaction Injection Molding".
ng in the Auto-motive
Industry', Journal of
Ceb. Plastics.

Vol, 2.1975; Plastics
for Auto-mobile Safety Bum
pers” + Journal of Ceb.P
Lastics+Vol. 2.1973° (Problems to be Solved by the Invention) Among the above raw materials, chain extenders are particularly important because they have a large influence on moldability and physical properties. As a chain extender, -
Low molecular weight alkanediols or certain aromatic polyamines are used for boat fishing, but neither of them necessarily provide sufficient performance in terms of moldability or physical properties.

For example, when ethylene glycol is used, cell roughness, loose skin, pinholes, sink marks, and dry spots are likely to occur, and when carried out industrially, productivity is extremely low and unsatisfactory.

The above method also has poor curing properties and heat resistance, so as an improvement method, there is a method of using ethylene glycol and an aromatic polyamine in combination. For example, JP-A-52-77
Publication No. 200 describes a method for improving curing properties and heat resistance by using ethylene glycol and a polynuclear mixed aromatic polyamine composition synthesized by condensation of aniline and formalin. However, with this method, the flowability of the mixed liquid within the mold is reduced, and the disadvantages of the above method, such as cell roughness, pinholes, sink marks, etc., cannot be sufficiently improved. Despite the above-mentioned drawbacks, the above methods are still being unsatisfactorily adopted in domestic production sites.

As another method, for example, in JP-A-56-109216, a relatively large amount of aliphatic amine is used in combination with ethylene glycol to improve mechanical strength and heat resistance. However, this method mainly uses ethylene glycol as a chain extender, so it cannot achieve significant improvements in mechanical strength and heat resistance. The present inventors have confirmed that the aliphatic amine itself, which has a relatively large molecular weight, does not significantly improve curing properties and heat resistance.

On the other hand, as a method of using an aromatic amine as the main chain extender, for example, as described in Japanese Patent Publication No. 54-17359, there is a method for using hydrogen at the ortho position to each amino group of an aromatic diamine. There is a method in which the amino group is substituted with a straight-chain alkyl having 1 to 3 carbon atoms to reduce the reactivity of the amino group due to steric hindrance, thereby improving the liquid flow into the mold.

Currently, this type of aromatic diamine method is rarely used in the United States because it has faster demolding time and curing time than ethylene glycol 1,4-butanediol, and has excellent heat resistance and tensile properties. Diethyltoluenediamine (hereinafter abbreviated as DETDAL) shown in the examples of the patent is used in products such as bumpers and fascias. However, since the activity of the aromatic diamine is still too high in this method, a large molding machine is required, resulting in a very large capital investment, or it is difficult to manufacture large, complex-shaped molded products or thin-walled molded products. In this case, it is not possible to obtain a good molded product, and if a large amount of DETDA is used, the molded product becomes brittle and easily cracks during demolding, and tends to cause sink marks.

Further, as another method, for example, JP-A-58-32626
There is a method of using a halogen-containing diaminobenzene with low reactivity as a chain extender, as disclosed in the above publication. In this method, the reactivity of halogen-containing diaminobenzene is moderately fast, but curing is slow and molding is impossible.

(Means for Solving the Problems) As a result of intensive research on aromatic polyamine compounds, the present inventors have discovered that by using diaminodiphenyl ether as the main chain extender, they can eliminate the shortcomings of conventional aromatic polyamines. The present invention was achieved by discovering that it is free from brittleness during molding and has appropriate liquid flowability. That is, the present invention provides a) polyisocyanate b) high molecular weight active hydrogen-containing compound C> diaminodiphenyl ethers represented by formula (1) (wherein R1 and R1 are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms) represents a group, an alkoxy group, or a chlorine atom.However, RI and R1 cannot be an alkyl group at the same time.

) d) A method for producing a polyurethane or polyurea elastic elastomer molded article, which comprises reaction-injection molding a mixed composition comprising an auxiliary agent in a closed mold.

Diaminodiphenyl ethers used in the present invention include, for example, 4,4'-diaminodiphenyl ether, 3.4°-diaminodiphenyl ether, 2.4°-diaminodiphenyl ether, 2.3°-diaminodiphenyl ether, 3-methyl-4,4°- Diaminodiphenyl ether 3-ethyl-4,4°-diaminodiphenyl ether 2-methyl-4,4°-diaminodiphenyl ether 3-chloro-4,4'-diaminodiphenyl ether 2-chloro-4,4°-diaminodiphenyl ether 2-methyl- 3,4'-Diaminodiphenyl ether 3'-methyl-3,4'-diaminodiphenyl ether, or a mixture of two or more thereof.

In addition to the above diaminodiphenyl ethers, the following chain extenders may also be used in combination. For example, alkanediols such as ethylene glycol, propylene glycol, l,4-butanediol; aliphatic diols such as ethylene diamine, propylene diamine, butylene diamine, etc. system amine; 4.4°
There are aromatic polyamines such as -methylenebis-(aniline), diaminoindan compounds, aromatic polyamines having an alkoxy group or chloro group at the ortho position of the amino group, meta-toluene diamine, meta-phenylene diamine, and the like.

Also, low molecular weight alkanolamines such as jetanolamine and triethanolamine; low molecular weight polyols obtained by adding propylene oxide or ethylene oxide to ethylene diamine, meta-toluene diamine, 4,4°-methylenebis(aniline); glycerin, triethanolamine, etc. Low molecular weight polyols such as methylolpropane; other so-called crosslinking agents may also be used.

Examples of the polyisocyanate used in the present invention include:
4.4°-diphenylmethane diisocyanate, 2.4
- and/or 2.6-tolylene diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, isophorone diisocyanate, other aliphatic polyisocyanates, and dimers, trimers, and carbodiimide modifications of these isocyanates. body,
These include allophanate modified products, biuret modified products, prepolymers, etc.

A particularly preferred isocyanate compound is a modified form of 4,4°-diphenylmethane diisocyanate, which is liquid at room temperature. Specific examples of this compound include: 4,4
"-Urethane group-containing polyisocyanate obtained by reacting diphenylmethane diisocyanate with a low molecular weight diol or triol (preferably polypropylene glycol having a molecular weight of less than 700), or 4,4"-containing carbodiimide and/or uretonimine groups Diphenylmethane diisocyanate-based polyisocyanate. Examples of preferred polyisocyanates include; products obtained by modifying a mixture of 2,4'- and 4.4°-diphenylmethane diisocyanates as described above, or 4,4° modified as described above;
- A mixture of diphenylmethane diisocyanate and a small amount of a diphenylmethane-based polyisocyanate having a higher functionality than difunctionality.

The high molecular weight active hydrogen-containing compound used in the present invention is an active hydrogen compound having a practical molecular weight of 1,000 to 18,000, and specifically includes the following compounds. Ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1.
3.6-hexanetriol, pentaerythritol,
Polyether polyols obtained by addition polymerizing alkylene oxide to polyhydric alcohols such as sorbitol; also alkanolamines such as jetanolamine and triethanolamine, ethylenediamine, diethylenetriamine, ammonia, aniline, tridinediamine,
Polyether polyol obtained by addition polymerization of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. to amines containing two or more active hydrogens such as xylylene diamine and diaminodiphenylmethane; polyether polyol obtained by ring-opening polymerization of tetrahydrofuran. Polytetramethylene ether glycol etc.

In addition, a polymer polyol obtained by grafting an ethylenically unsaturated compound such as styrene, acrylonitrile, or methyl methacrylate to the above polyol, and 1,
2- or 1,4-polybutadiene polyols or hydrogenated products thereof can also be used.

Furthermore, polyether polyamine σ obtained by reacting a polycarboxylic acid with a low molecular weight polyol, and polyester polyol and polycarbonate polyol obtained by ring-opening polymerization of caprolactone can also be used.

In addition to the above high molecular weight active hydrogen-containing compounds, for example,
A primary or secondary amine obtained by aminating the OH group of the above polyether polyol, specifically a polyether polyol obtained by addition polymerizing propylene oxide to glycerin, in the presence of a catalyst with ammonia or an alkyl amine. There are high molecular weight polyether polyamines obtained by the reaction. Alternatively, it may be a polyether polyamine obtained by hydrolyzing a prepolymer obtained by reacting a polyether polyol and an isocyanate, or a polyether polyamine obtained by chemically bonding a high molecular weight polyether and an aromatic amine. It may be.

When carrying out the present invention, the equivalent ratio of NGO groups and active hydrogen-containing compounds contained in the polyisocyanate is from 0.8 to
Adjust the amount of each raw material used so that it becomes 1.3.

Auxiliary agents used in the present invention include catalysts, blowing agents, internal mold release agents, fillers, pigments, antioxidants, weathering stabilizers, and the like.

Examples of catalysts include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, tin oleate, and tin octoate, and triethyleneamine, N.

N, N', N'-tetramethylpropanediamine,
1.4-diazabicyclo-(2,2,2)-octane,
An amine catalyst such as pentamethyldiethylenetriamine.

As a blowing agent, for example, trichlorofluoromethane, C
CI□F-CC+F, methylene chloride, water, nitrogen gas, carbon dioxide gas, etc.

As the internal mold release agent, silicone type, fatty acid amide, etc. are used.

Fillers include glass fiber, flake glass, mica,
Talc, inorganic compound whiskers, etc. are used.

(Function) In the present invention, by using the above-mentioned diaminodiphenyl ethers, molding problems that could not be solved with conventional chain extenders can be solved.

(Example) A mixed solution was prepared using the following raw materials, and RIM molding was performed in a mold using an injection molding machine for polyurethane.

± Raw ± Two Earths and Two Earths: A polyoxyalkylene triol with a hydroxyl value of 28 mgKOH/g and a primary hydroxyl group content of 75% obtained by addition polymerizing propylene oxide and ethylene oxide to glycerin.

"J] 2-2"-: Polyoxyalkylene diol having a hydroxyl value of 28 mgKOH/g and a primary hydroxyl group content of 80% obtained by addition polymerizing propylene oxide and ethylene oxide to propylene glycol.

Bo 1 Aer Bo! Amine-1: 80% terminally secondary polyether polyamine obtained by reacting a polyol with a molecular weight of about 5000 obtained by addition polymerization of propylene oxide to glycerin with isopropylamine in the presence of a catalyst.

incyane-1=Isocyanate prepolymer with an NCO group content of 26% obtained by reacting 4,4°-diphenylmethane diisocyanate and tripropylene glycol.

±Yue Qy2 soil: A mixture of 3,4'-diaminodiphenyl ether and 2,4'-diaminodiphenyl ether in a weight ratio of 60:40.

Weight ratio of 3,4°-diaminodiphenyl ether and 2,4'-diaminodiphenyl ether is 4
0:60 mixture.

2-Methyl-3,4'-diaminodiphenyl ether, manufactured by LONZA Co., Ltd.
So, 3,5-diethyl-2,4-diaminotoluene and 3
．． A mixture of 5-diethyl-2,6-diaminotoluene in a weight ratio of 80,720.

” 1 connection ≦ 2 J-: “m-TD” manufactured by Mitsui Toatsu Chemical ■
A' is a mixture of 2,4-diaminotoluene and 2,6-diaminotoluene in a weight ratio of 80:20.

L-102Q: Catalyst for urethane manufactured by Mitsui Toatsu Chemical Co., Ltd. 1:2 of triethylenediamine and dipropylene glycol
blend.

B-712: External mold release agent for urethane RIM manufactured by Middle East Yushi ■.

Example 1 (sheet molding) A molding test was conducted using the following raw material composition.

(Resin) Polyol - b00 parts by weight Polyamine - 125 parts by weight L - 1020 1,0 parts by weight (Isocyanate) Polyisocyanate - 151 parts by weight (Isocyanate index = 105) The reaction injection molding machine used is NR-230 manufactured by Toho Kikai ■. did. The temperature of the resin and isocyanate was adjusted to 40°, the blending ratio was adjusted to the above amount, and the injection speed was 330 g /
The mixture was injected into the mold at sec.

A 2.5 mm sheet mold was used as the mold. After heating to 75°C, an external mold release agent was applied and the mold was thoroughly wiped with a dry cloth.

The mold was removed 30 seconds after injection, and the releasability and curing properties were compared. Cure performance was determined by placing the sheet molded product on a horizontal table immediately after demolding, and measuring the height of the drop from the horizontal surface by protruding 20 cm from the tip of the sheet after 1 minute, and determining the quality of the cure performance based on its size. . At the same time, in order to see how brittle the sheets were immediately after being formed, the sheets were bent to see if they would crack.

The surface condition of the molded product was also examined. Furthermore, the value obtained by dividing the filling distance (c + s) to the tip of the sheet by the total sheet weight (g) was defined as the "liquid flow index (am/g) J" to examine the liquid flow properties.The liquid flow index is the value The larger the value, the better the liquid flow.

Physical properties were determined by cutting a test piece from the molded product, heating it at 120°C for 1 hour, and then measuring tensile strength, elongation, bending modulus, and heat resistance. Heat resistance test is 2c+aX1
A 5cm strip-shaped test piece was fixed horizontally at a position 5Cb from one end, and after being left in a constant temperature of 120"C for 1 hour, the vertical distance that the other end sags (heat sag) was measured. The heat resistance was then compared.

The results were as shown below.

(Moldability) Liquid flow index (cm/g) 0. 099 Grinding strength (sec) 15 20c+m Overhang sag (c+++) 10 Brittleness immediately after demolding None, no flakes, no sink marks, physical properties) Density (g/c+1) 1. 05 Tensile strength (kg/cd) 300 Elongation (%)
340 Bending modulus (kg/d) 1920 Heat sag (■m
) 5.0 Example 2 (Sheet molding) Sheet molding was carried out under the same conditions as in Example 1 except that polyamine-1 in Example 1 was changed to polyamine-2.

The results were as shown below.

(Moldability) Liquid flow index (cm/g) 0. 107 Green strength (seconds) 15 Sag of 20cm overhang (cm) 12 Brittleness immediately after demolding: None, no flakes, no sink marks, physical properties) Density (g/c+J) 1. 06 Tensile strength (kg/aj) 260 Elongation (%)
435 Bending modulus (kg/c+fl) 1800 Heat sag (
o1g@) 5. 5 Example 3 (Sheet molding) Sheet molding was carried out under the same conditions as in Example 2 except that the polyamine-2 in Example 2 was changed from 25 parts by weight to 30 parts by weight.

The results were as shown below.

(Moldability) Liquid flow index (Cm/g) 0. 091 Grinding strength (sec) 15 20c-Protrusion sag (cm) 6 Brittleness immediately after demolding No flaky residue Physical properties) Density (i/cd) 1, 06 Tensile strength (
kg/cj) 420 elongation (%)
300 Bending modulus (kg/c+a) 2860 Heat sag (f
fl@) 3. 3 Comparative Example 1 (Sheet molding) Sheet molding was carried out under the same conditions as in Example 3 except that polyamine-2 in Example 3 was changed to polyamine-4.

The results were as shown below.

(Moldability) Liquid flow index (cm/g) 0. 088 Grind strength (sec) 15 20cm protrusion sag (cm) 4 Brittleness immediately after demolding Yes No flaky residue Physical properties) Density (g/c () 1, 05 Tensile strength (kg/c + 4) 400 Elongation (%)
280 Bending modulus (kg/c+a) 3020 Heat sag (m
+*) 2. 0 Obviously, Comparative Example 1 is
Compared to Example 3 of the present invention, the liquid flowability was poor and the sample was brittle immediately after demolding.

Example 4 (Sheet molding) Sheet molding was carried out under the same conditions as in Example 1, except that polyamine-1 in Example 1 was changed to polyamine-3, polyol-1 was changed to polyetheramine-1, and the catalyst was removed.

The result is as shown below.

(Moldability) Liquid flow index (C/g) 0.089 Grinding strength (sec) 15 Sag of 20cm overhang (cm) 8 Brittleness immediately after demolding None, no flaky residue, no sink marks, physical properties) Density (g) /c+1) 1. 07 Tensile strength (kg/c+1) 310 Elongation (%)
360 Bending modulus (kg/cj) 2010 Heat sag (+u
+) 4. 0 (Effect) As is clear from Examples 1 to 4, the method of the present invention was found to have better molding performance than the prior art during injection molding of polyurethane.

Claims (1)

[Claims] a) Polyisocyanate b) High molecular weight active hydrogen-containing compound c) Diaminodiphenyl ether represented by formula (1) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (1) (In the formula, R ^1 and R^2 represent a hydrogen atom, an alkyl group or alkoxy group having 1 to 4 carbon atoms, or a chlorine atom; however, R^1 and R^2 cannot be an alkyl group at the same time.) d ) A method for producing a polyurethane or polyurea elastic elastomer molded article, which comprises reaction-injection molding a mixed composition comprising an auxiliary agent in a closed mold.