JPH02269726A - Production of polyurethane urea and its molding - Google Patents

Abstract

PURPOSE:To obtain an elastic molding having a dense skin by reaction-injection- molding a mixture of a polyisocyanate, a high-MW polyether polyol, a specified diamine, a fatty acid salt of Bi, and an organic acid. CONSTITUTION:A polyurethane urea molding is obtained by reaction-injection- molding a mixture of a polyisocyanate (a), a polyether polyol (b) of an MW of 1000-18000, 1,3,5-triiso-propyl-2,4-diaminobenzene (c), a fatty acid salt (d) of Bi, and an organic acid (e) in a sealed mold. A desirable range of the amount of component (c) used is 15-45 pts.wt. per 100 pts.wt. component (b). When the amount of component (c) used is excessively large, the molding is unsuitable for actual use because of its low impact resistance and when it is excessively small, the molding is unsuitable for actual use because of its excessively low rigidity.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polyurethane urea elastomer produced by reaction injection molding technology, and more specifically, it relates to a polyurethane urea elastomer produced by reaction injection molding technology, and more specifically, it relates to a polyurethane urea elastomer made of a highly reactive polyisocyanate, a high molecular weight polyether polyol, and an aromatic amine chain. The present invention relates to a method for producing an elastic molded article having a dense skin by reaction injection molding technology using an extender, and the elastic molded article obtained thereby.

(Prior Art) Polyurethane elastic molded products having a dense surface and excellent physical properties, moldability, and appearance are widely used. Specific examples of applications include automobile boards, sports and leisure goods, office equipment housings, furniture, agricultural equipment, etc. The most commonly used of these are automobile bumpers, fascias, doors, side moldings and the like.

Incyanate compound larvae and incyanate reactive compounds (
It is known to mold non-foamed polyurethanes, fiber-reinforced elastomers or microcellular polyurethane elastomers by reaction injection molding by polyaddition with active hydrogen compounds). The raw materials for these polyurethanes are usually
These include polyisocyanates, polyether polyols and polyester polyols having hydroxyl groups, chain extenders and catalysts, as well as appropriately used blowing agents, auxiliaries, additives and fibrous inorganic compounds. The reaction injection molding method is Re
action injection molding
(hereinafter referred to as RIM), the isocyanate compound and the inocyanate-reactive component mixture are impingement-mixed under pressure (often under high pressure) using a mixing injection machine, and this mixture is filled into a mold and cured, followed by a molded product. This is a method to extract the . A detailed description of RIM can be found, for example, in the following document: “Reaction Injection Molding in the Automotive Industry” Journal of Cell Plastics Vol. 1. ,2.197
5 years old Reaction Injection Mold
ing in the Auto-motiveInd
ustry, Journal of Ce11.
Plastic, Vol, 2゜1975:) r
"Plastics for Automobile Safety Bumpers" Journal of Cell Plastics Vol. 1. L1973 (“Pl
astics for Auto-Mobile S
afetyBumpers, Journal of
Ce11. Plastic, Vol, 2゜19'73
) Among the raw materials used above, the chain extender and the catalyst are particularly important because they have a great influence on moldability and physical properties. As a chain extender, ethylene glycol has conventionally been generally used, and recently diethyltoluenediamine (hereinafter referred to as DETDA) has been used. Further, as a catalyst, a combination catalyst of a tin catalyst such as dibutyltin dilaurate and an amine catalyst such as triethylenediamine is usually used. For example, in Japanese Patent Publication No. 54-17359, R
IM urethane urea composition (hereinafter referred to as DETDA method)
is disclosed.

According to this method, a urethane urea elastomer having a short demolding time (curing time) and excellent heat resistance and tensile properties can be obtained. Currently, it is used in most products such as bumpers or fascias in the United States. The disadvantage of this method is that the activity is still too high, making it necessary to use a large molding machine, resulting in a very large investment in equipment.

In addition, since the discharge time is short, when manufacturing large-sized molded products, complex-shaped molded products, or thin-walled molded products, it is difficult to obtain molded products with good molding conditions. As a method for improving this method, there are, for example, the following documents and patents.

"Structure-Property Relationship of Chain Extenders: Highly Processable Aromatic Diamines for RIM" Polyurethane Technology/Marketing 30th Annual Conference, October 15-17, 1986
Chain Extender 5structure
-Physical Property Pe1ati
onships: HighlyProcessab
le Aromatic Diamine For R
IM” 30THANNLIAL POLYURETf
(ANE TECI(NICAL/MARKETING)
CONFERENC:E, 0CTOBER, 15-1
7, 1986), JP-A No. 62-50320, the above-mentioned documents and publications contain ter as an aromatic amine.
A method for obtaining a RIM urethaneurea molded product using t-butyltoluene diamine (t-BTDA) and a combination catalyst of dibutyltin dilaurate and triethylene diamine (hereinafter referred to as the t-BTDA method)
is disclosed.

(Problem to be solved by the invention) Compared to the DETDA method, the t-BTDA method allows demolding in less than 30 seconds despite its lower activity, and in formulations with high surface rigidity, It has the advantage of low surface rigidity and easy demolding work. However, as described in the above literature, the heat resistance (heat sagging resistance) of the product molded product is inferior to that of the DETDA method;
Therefore, for example, in automotive applications, there is a problem in that heat sag occurs when applying metallic paint. Furthermore, in formulations with low surface rigidity, the hardness upon demolding becomes too low, causing problems in shape retention. In addition, we have investigated reducing the activity of DETDA by changing the type, amount, and ratio of the amine catalyst and the tin catalyst, which were conventionally disclosed in the DETDA method.
In either case, the initial strength only decreased and the problem was not solved.

As described above, none of the conventional methods have been satisfactory in terms of moldability and physical properties.

(Means for Solving the Problems) The present inventors have conducted extensive studies to develop a method that has short demolding time, good moldability, and excellent physical properties such as shape retention and heat resistance. In particular, it has been discovered that the purpose can be achieved by using a specific aromatic diamine as a chain extender in combination with a specific catalyst system, and the present invention has been achieved.

That is, the present invention comprises (a) polyisocyanate (b) polyether polyol having a molecular weight of 1,000 to 18,000 (c) 1,3,5-)liisobrobyl-2,4-diaminobenzene (d) Bi fatty acid salt and (e ) A method for producing a polyurethaneurea molded product, which comprises reaction-injection molding a mixture containing an organic acid and, optionally, (f) a blowing agent, an internal mold release agent, a filler, and other auxiliaries in a closed mold. The present invention provides a molded article obtained in this manner.

The component (C) used in the present invention is 1°3.5-triisopropyl-2,4-diaminobenzene.
It is a compound obtained by nitrating and reducing 5-triisopropylbenzene, and is a diamine with a melting point of 71 to 72°C and a solid at room temperature. The preferred amount range of this diamine component (C) is 15 to 45 parts by weight per 100 parts by weight of the polyether polyol of component (b). If the amount is too low, the molded product will have too low rigidity, making it unsuitable for practical use.

The fatty acid salt of Bi as component (d) of the present invention is a salt of a fatty acid prepared by RCOOH, R is an f-alkyl group, an aryl group, an aralyl group, or an aralkyl group having 1 to 21 carbon atoms, and ( R is methyl, ethyl, propyl, isopropyl, neopentyl, octyl, neononyl, cyclohexyl, tridecyl, neodecyl, nonadecyl,
Tolyl and naphthyl are preferred. This usage amount is the component (b)
) 0.01 to 5% by weight based on the polyether polyol
shall be.

The organic acid of the component (e) of the present invention has a small number of groups showing rapidity such as C0OH group, So, H group, and phenolic OH group (both 1 and 1).
It is a compound with a long-lasting effect. Particularly preferred are fatty acids, oxycarboxylic acids, aliphatic dicarboxylic acids, aromatic carboxylic acids, sulfonic acids, nonylphenol, and the like. For example, specific examples include 2-ethylhexanoic acid, neodecanoic acid, adipic acid,
Examples include benzoic acid, catechol, lactic acid, and dodecylbenzenesulfonic acid. The amount of this organic acid used is the component (b)
) is preferably 0.01 for the polyether polyol.
~5% by weight.

The polyisocyanate used as component (a) in the present invention is not particularly limited (although conventionally used polyisocyanates can be used; for example, 4,4'-diphenylmethane diisocyanate, 2,4- and/or .6-
)-lylene diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate,
Isophorone diisocyanate, other aliphatic polyisocyanates and dimers of these incyanates,
Examples include trimer, carbodiimide modified product, allophanate modified product, Biuret modified product, prepolymer, and the like.

Among these polyisocyanates, particularly preferred incyanate compounds for the present invention are derivatives of 4,4'-diphenylmethane diisocyanate, which is liquid at room temperature. Specific examples of this compound include: urethane group-containing polys obtained by reacting 4,4'-diphenylmethane diisocyanate with a low molecular weight diol or triol (preferably polypropylene glycol having a molecular weight of less than 700). Isocyanate: 4,4'-diphenylmethane diisocyanate-based polyisocyanate having carbodiimide groups and/or urethane imine groups. Examples of preferred polyisocyanates also include: 2,4'- and 4.
A modified product prepared by modifying a mixture of 4'-diphenylmethane diisocyanate as described above: 4,4'-diphenylmethane diisocyanate modified as described above and a small amount of diphenylmethane-based diisocyanate having a higher functionality than the difunctionality. and mixtures with polyisocyanates containing polyisocyanate.

The long-chain molecular polyol used as component (b) in the present invention is also not particularly limited, and examples thereof include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3.6- Molecular weight 1000 obtained by addition polymerizing alkylene oxide to polyhydric alcohols such as hexanetriol, pentaerythritol, sorbitol and/or these polyhydroxy compounds
There are ~18,000 polyether polyols. In addition, alkanolamines such as jetanolamine and triethanolamine, amines containing two or more active hydrogens such as ethylene diamine, diethylene triamine, ammonia, aniline, tolylene diamine, xylylene diamine, and diaminodiphenylmethane, ethylene oxide, propylene oxide, etc. , butylene oxide, styrene oxide, etc., with a molecular weight of 1000 to 18.
000 polyether polyols and polytetramethylene ether glycols can also be used.

In addition to the above, higher fatty acid ester polyols and polyester polyols obtained by reacting polycarbonate with low molecular weight polyols, polyester polyols obtained by polymerizing caprolactone, polycarbonate polyols, castor oil, dehydrated castor oil, and other hydroxyl group-containing high grade Fatty acid esters can also be used.

Furthermore, polymer polyols obtained by grafting ethylenically unsaturated compounds such as styrene, acrylonitrile, and methyl methacrylate to the above-mentioned known polyols, and 1.2- or 1.4-polybutadiene polyols or hydrogenated products thereof are also available. Can be used. These polyols may be used alone or in combination of two or more.

In carrying out the present invention, polyisocyanate (component (
Adjust the amount of each raw material used so that the equivalent ratio of the NGO group contained in a)) to the active hydrogen contained in the polyol and aromatic polyamine (component (C)) is 0.8 to 1.3. do. If the equivalent ratio is less than 65,018 or more than 1.3, physical properties such as heat resistance and weather resistance of the molded product will deteriorate.

In the present invention, blowing agents, internal mold release agents, fillers, etc. as auxiliary agents of component (f) may be added as necessary, and those known in the production of polyurethane or polyurethane urea moldings by the RIM method may be used. Yes, there are no particular restrictions.

As a blowing agent, for example, trichlorofluoromethane, C
CI z F '' CG IF *, methylene chloride, water, nitrogen gas, carbon dioxide gas, etc.

There are many types of internal mold release agents, including silicone-based ones, fatty acid metal salts, fatty acid amide derivatives, and fatty acid ester derivatives.

Glass fiber and flake glass are used as fillers.

Examples include mica, talc, and inorganic compound whiskers.

Other auxiliary agents include pigments such as carbon, antioxidants,
There are weathering stabilizers, etc.

In the present invention, the RIM molding technique itself can be carried out according to a known method, for example, the method detailed in the above-mentioned literature, and can be carried out in various ways depending on the purpose.

The feed rate of the reaction mixture into the mold is generally 0.85-1.15 g/c rd, for example for bumper molding.
Preferably, the amount is such that a molded article of
However, if mineral fillers are used, the density of the molded article can exceed 1.2 g/crrr. The molded article may remain in the mold for preferably at least 20 seconds - more preferably for 30 seconds before being removed from the mold.

Generally, the reaction mixture can be fed to the mold at a starting temperature of 25-60<0>C, preferably 30-50<0>C. The temperature of the mold itself is generally 60-120°C, preferably 60-8°C.
It is 0°C.

(Effects of the Invention) According to the method of the present invention, it is possible to produce a polyurethane urea molded product with a dense skin, which has a short demolding time, good moldability, and excellent physical properties such as shape retention, strength, and heat resistance. Furthermore, according to the present invention, there is no need for a RIM machine with a particularly high discharge power.

The products according to the present invention are suitable for use in a wide variety of applications such as automobile boards, sports and leisure goods, and housings for office equipment.

(Examples) Next, the present invention will be described in more detail based on Examples. The following raw materials were used in the examples.

Polyol A: Polyoxyalkylene triol with a hydroxyl value of 28 mgKOH/g and a primary hydroxyl group content of 75%, obtained by addition polymerization of 15% by weight of propylene oxide and ethylene oxide to glycerin, and a molecular weight of about 6,000 isocyanate A diphthalate. NC obtained by reacting a mixture of enylmethane diisocyanate and its carbodiimide modified product with tripropylene glycol
Repolymer with 23% O group content, molecular weight 370 Examples 1 to 4 (sheet mold molding test) Polyol A, 1.3.5-)-lyisobrobyl-2 with the composition (parts by weight) shown in Table 1. .4-Diaminobenzene and bismuth-tris (neodecanoate) as a fatty acid salt of bismuth
A resin solution was prepared by mixing neodecanoic acid, dodecylbenzenesulfonic acid, adivic acid, or nonylphenol as an organic acid. This resin liquid was reacted with Incyanate A using a reaction injection molding machine.

The reaction injection molding machine is LRM- manufactured by Cincinnati Milacron.
L15 type was used. The mold is 900noax600mm
A sheet mold of X 3 , Omm was heated to 70°C.

The temperature of the stock solution was adjusted to 40° C., and the flow rate ratio of the resin solution to the incyanate component was adjusted to be the amount described in Table 1. Dry nitrogen gas was mixed and dispersed in the resin liquid in an amount of 15% by volume, and the mixture was injected into the mold at an injection speed of 1000 g/Sec.

Demold the mold 30 seconds after injection, and determine whether the mold releasability is good (when the molded product is removed from the mold, whether or not a part of the molded product remains on the mold surface, and if no part remains, it is considered good. ), and compared the elasticity immediately after demolding. Immediately after demolding, the molded product was bent 180 degrees and the time required for no cracks to occur was measured, and the green strength was determined. Visually inspect the surface condition of the molded product, that is, the presence or absence of surface defects, and calculate the liquid flow index (11 m/g) by dividing the filling length (mm) to the tip of the sheet by the total sheet weight (g). The larger the value of the liquid flow index, the more
Indicates good liquid flow.

In addition, test pieces were cut from the molded product to determine the tensile strength, elongation,
Bending modulus and heat resistance were measured. Heat resistance test is 2c
5co+ from one end of a short strip-shaped test piece of m x 15cm
Fix it horizontally at the position and place it in a thermostatic oven at 120℃.
Leave it for a while. After being left standing, the distance that the other end sagged (thermal sag) was measured and the heat resistance was compared.

The results are shown in Table 2.

Comparative Example 1 Dibutyltin dilaurate and D instead of bismuth-tris(neodecanoate) and neodecanoic acid as catalysts
ABCO33L V (AirProducts a
RIM molding was performed in the same manner as in Example 1 using the same composition except that the amount of ND Chemicals Inc. shown in Table 1 was used. The moldability and physical properties of the molded product are
Shown in the table.

Comparative Example 2 DETDA as aromatic diamine instead of 1.3.5-triisopropyl-2,4-diaminobenzene, dibutyltin dilaurate and DAB instead of bismuth-tris(neodecanoate) and neodecanoic acid as catalyst
RIM molding was performed in the same manner as in Example 1 with the same composition except that CO33LV was used in the amounts shown in Table 1. The results obtained are shown in Table 2.

As is clear from comparing Examples 1 to 4 with Comparative Examples 1 and 2, the method of the present invention shows better molding performance and demolding performance than the conventional method during injection molding of polyurethane, and It was also recognized that the physical properties of the product, such as heat resistance, were excellent.

Claims (2)

[Claims] (1) (a) Polyisocyanate (b) Polyether polyol having a molecular weight of 1000 to 18000 (c) 1,3,5-triisopropyl-2,4-diaminobenzene (d) Fatty acid salt of Bi and (e) A method for producing a polyurethane urea molded article, which comprises reaction-injection molding a mixture containing an organic acid in a closed mold. (2) A polyurethaneurea molded article obtained by the method of claim (1).