JPH02269727A - Production of polyurethane urea elastomer and its molding - Google Patents

Abstract

PURPOSE:To obtain an elastic molding having self-releasability by reaction- injection-molding a mixture of a polyisocyanate, a high-MW polyether polyol, a specified aromatic diamine, a fatty acid salt of Bi, an organic acid, and a specified internal releasing agent. CONSTITUTION:A polyurethane elastomer is produced by reaction-injection- molding a mixture of a polyisocyanate, a polyether polyol of an MW of 1000-18000, an aromatic diamine selected from among 2,4-diamino-5-tert- butyltoluene, 2,6-diamino-3-tert-butyltoluene, 3,4-diamino-5-butyltoluene and 2,3- diamino-4-tert-butyltoluene, a fatty acid salt of Bi, an organic acid, and an internal mold releasing agent having a free acid group and/or a free acid salt group. As the polyisocyanate, a 4,4'-diphenylmethane diisocyanate derivative which is liquid at room temperature is particularly desirable.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a polyurethaneurea elastomer by reaction injection molding technology, and more specifically, it relates to a method for producing a polyurethane urea elastomer by reaction injection molding technology, and more specifically, it relates to a method for producing a polyurethaneurea elastomer using a reaction injection molding technique, and more specifically, it relates to a method for producing a polyurethane urea elastomer using a reaction injection molding technique. The present invention relates to a method for producing an elastic molded article having self-releasing properties by reaction injection molding technology using a group amine chain extender and a self-releasing agent, and to an 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 applications include automobile boards, sports and leisure goods, office equipment housings, furniture, agricultural equipment, and many more. The most commonly used of these are automobile bumpers, fascias, doors, side moldings and the like.

Isocyanate compounds 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 Kuroiso 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. 1.2.1975
Year (“Reaction Injection Mold
ing in the Auto-motiveInd
ustry, Journal of Ce11.
Plastic, Vol. 2゜1975) ``Plastic for automobile safety bumpers'' Journal of Cell Plastics Vol. 1.2゜1973
Sticks for Auto-Mobile Sa
fetyBumpers, Journal of
Ce11. Plastic, Vol. 2゜Polyurethane urea elastomer is extremely easy to adhere to metal during the curing process, and to prevent this, a common method is to apply a release agent such as wax or metal soap to the inner surface of the mold. It is being

In this case, the inner surface of the mold must be completely covered with a mold release agent, and in this method, it is necessary to apply the mold release agent every time a molding is performed. In addition, the old mold release agent that remains and accumulates will impair the gloss and surface properties of the molded product, so the mold release agent that remains on the metal surface must be removed and the surface cleaned every time it is molded. , requires a lot of effort.

On the other hand, a method for producing a polyurethaneurea elastomer having self-releasing properties by adding a compound having mold-releasing properties to a polyurethaneurea raw material mixture has also been studied, and the mold-releasing agent added to the mixture is an internal mold-releasing agent. being called. It has also been confirmed that by adding an internal mold release agent, the number of times the mold release agent is applied to the inner surface of the mold can be significantly reduced. As an internal mold release agent, an organic silicon compound (Japanese Patent Application Laid-Open No. 57-157
No. 739), higher fatty acid ester (No. 63-17276)
No. 4), higher fatty acid metal salts (No. 61-83215), and the like are known.

(Problem to be solved by the invention) However, higher fatty acid esters as internal mold release agents have insufficient mold release effects, and higher fatty acid metal salts are often solid at room temperature and are insoluble in high molecular weight polyols. In many cases, higher fatty acid metal salts remain solid,
Even when added to an active hydrogen compound, it has no mold release effect, and when used as an internal mold release agent, it must be dissolved in a dissolving agent.

Therefore, polyfunctional amines are usually used as solubilizing agents. However, the addition of higher fatty acid metal salts has disadvantages such as lowering the physical properties, particularly mechanical strength, of the polyurethane urea elastomer and deteriorating surface properties.

On the other hand, organic silicon compounds with relatively little deterioration in physical properties have extremely good mold release properties due to their characteristics, but several improvements have been made to solve the problems of paint repellency and poor adhesion of paint films during painting. It has been tried. A typical example is an organosilicon compound in which functionality is imparted to an isocyanate by adding an active hydrogen atom to the side chain or end of a dimethylsiloxane compound. However, these attempts were not able to completely prevent repellency during painting or poor adhesion of the paint film.

In addition, if the internal mold release agent has free acid groups and/or free acid bases with carboxyl groups or phosphate residues, the effect of deterioration of physical properties is low, and no repellency or poor adhesion is observed. However, there were problems such as poor stability of the polyurethaneurea raw material mixture over time and inability to maintain initial performance.

The object of the present invention is to address the above-mentioned drawbacks of the conventional method for producing polyurethaneurea elastomers by reaction injection molding.
Decrease in the mechanical strength of the elastic body, 2) Repellency of the paint, 3) Poor adhesion of the paint film, 4) Poor stability of the raw material mixture over time.
5) To shorten the elastic body production cycle and simplify manufacturing operations by overcoming problems such as roughening of the surface of the elastic body and imparting self-releasing properties to the raw material mixture.

(Means for Solving the Problems) As a result of intensive study of various polyurethaneurea elastomer raw material mixtures, the present inventors unexpectedly found that a specific raw material mixture solves the problems described in the previous section.

That is, the present invention comprises (a) polyisocyanate (b) polyether polyol having a molecular weight of 1,000 to 18,000 (c) 2,4-diamino-5-tert-butyltoluene, 2
．． Aromatic diamine (d)Bi selected from the group consisting of 6-diamino-3-tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene, and 2,3-diamino-4-tert-butyltoluene A mixture containing (e) an organic acid, (f) an internal mold release agent having a free acid group and/or a free acid base, and (g) an appropriate blowing agent, filler, or other auxiliary agent is placed in a closed mold. The present invention provides a method for producing a polyurethaneurea elastomer characterized by reaction injection molding in a container, and an elastomer molded product obtained in this manner.

Component (C) used in the present invention, 2,4-diamino-5-tert-butyltoluene, 2,6-diamino-3-
Tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene, and 2,3-diamino-4-tert-butyltoluene are compounds obtained by alkylating toluenediamine, followed by nitration and reduction. . Japanese Patent Publication No. 61-931
No. 44 discloses its manufacturing method. The preferred amount range of this diamine component (C) is 15 to 45 parts by weight per 100 parts by weight of polyether polyol. If the amount of this diamine component (C) is too large, the impact resistance of the molded product will deteriorate, making it unsuitable for practical use.If the amount is too small, the rigidity of the molded product will become too low, 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 aridized with .RCOOH, and R is a carbon number of 1 to 21.
an alkyl group, an aryl group, an aralyl group, an aralkyl group, and in particular R is methyl, ethyl, propyl,
isopropyl, neopentyl, octyl, neononyl,
Cyclohexyl, tridecyl, neodecyl, nonadecyl, tolyl and naphthyl are preferred. This usage amount is based on the ingredient (
Preferably 0.0 for the polyether polyol of b)
The amount is 1 to 5% by weight.

The organic acid of component (e) of the present invention contains at least one acidic group such as a C0OH group, So, H group, or phenolic OH group.
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 internal mold release agent having a free acid as component (f) of the present invention is a so-called acidic compound having a pH of 7 or less and having a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, a boric acid group, etc. Also, the component (f
) is a compound having a salt of carboxylic acid, sulfonic acid, phosphoric acid, boric acid, etc. and an organic basic compound such as amine in its molecule. As this internal mold release agent, conventionally known ones can be used.

For example, the internal mold release agent having a free acid is a carboxy-functional siloxane compound as defined in the claims of Japanese Patent Publication No. GS-TX7S as an organosilicon compound.
Further, they are carboxylic acid, sulfonic acid, phosphoric acid, and boric acid derivatives having an alkyl group, aryl group, aralyl group, or aralkyl group with a large number of carbon atoms. JP-A-57-1
Typical examples thereof include phosphoric acid compounds defined in the claims of JP-A No. 74237 and sulfonic acid compounds defined in the claims of JP-A-55-160013. Typical internal mold release agents with free acid bases are amine salts of carboxylic acids, sulfonic acids, phosphoric acids, and boric acids having alkyl groups, aryl groups, aralyl groups, and aralkyl groups with a large number of carbon atoms. A typical example is the tall oil fatty acid salt used in Reference Example 2 of Publication No. 63-56887. The amount of this internal mold release agent used is preferably 0.01 to 5% by weight based on the polyether polyol of component (b).

The polyisocyanate used as component (a) in the present invention is not particularly limited, and conventionally used polyisocyanates can be used, such as 4,4'-diphenylmethane diisocyanate, 2,4- and/or 2- .6
-1-lylene diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, inphorone diisocyanate, other aliphatic polyisocyanates, dimers, trimers, carbodiimide modified products, allophanates of these isocyanates Examples include modified products, Biuret modified products, prepolymers, and the like.

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

The long-chain molecular polyol used as component (b) in the present invention is also not particularly limited (for example, 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, and 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. molecular layer 1000~1s obtained by addition polymerization
ooo 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 polycarboxylic acids 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.

Further, polymer polyols obtained by grafting ethylenically unsaturated compounds such as styrene, acrylonitrile, and methyl methacrylate onto the above-mentioned known polyols, and 1,2- or 1,4-polybutadiene polyols or hydrogenated products thereof. can also 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 this equivalent ratio is less than 0.8 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, fillers, etc. as auxiliary agents of component (f) may be added as necessary, and those known in the production of polyurethane or polyurethane urea molded products by the RIM method can be used, and there are no particular restrictions. There isn't.

As a blowing agent, for example, trichlorofluoromethane, C
CIYOF-CCIF, methylene chloride, water, nitrogen gas, carbon dioxide gas, etc.

In addition to the above raw materials, the following can also be added and used.

Fillers include glass fiber, flake glass, mica,
Examples include 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 1, for example, the method detailed in the above-mentioned literature, and can be carried out in various ways depending on the purpose.

The amount of the reaction mixture fed into the mold is generally 0.85 to 1.15 g/cn for bumper molding, for example. Preferably, the amount is such that a molded article of 1.2 g/crrl' is obtained; however, if mineral fillers are used, the density of the molded article may exceed 1.2 g/crrl'. The molded article may remain in the mold for preferably 20 seconds or more, more preferably 30 seconds or more before being removed from the mold.

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

(Effects of the Invention) The method of the present invention exhibits better molding performance and demolding performance than conventional compositions during injection molding of polyurethane, and reduces the physical properties of the obtained elastic body, roughens the surface, etc. It has an excellent effect of not showing poor adhesion to the paint and no repelling of the paint.

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 6000 incyanate A. NC obtained by reacting a mixture of phenylmethane 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, tert-butyltoluenediamine (Air Products Ch) with the composition (parts by weight) shown in Table 1
Bismuth-tris (neodecanoate) as a fatty acid salt of bismuth; neodecanoic acid, dodecylbenzenesulfonic acid, adipic acid, or nonylphenol as an organic acid; stearic acid as an internal mold release agent (referred to as internal mold release agent A); ) or an equimolar salt of tall oil fatty acid and amidamine (designated as internal mold release agent B), or carboxy-functional siloxane (Q 2-7119 Dow Cornig product, designated as internal mold release agent C), or a phosphoric acid compound (lecithin). , internal mold release agent) were mixed to form a resin. Reaction injection molding machine with resin liquid (resin premix) and isocyanate A! I made a reaction.

The reaction injection molding machine is LRM- manufactured by Cincinnati Milacron.
L15 type was used. The mold is 900mmX600mmX
3. A 0 mm sheet mold 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 shown in Table 1. Dry nitrogen gas was mixed and dispersed in the resin solution in IS volume %, and the mixture was injected into the mold at an injection speed of 1000 g/sec.

Remove the mold 30 seconds after pouring, and determine whether the mold release property is good or not (when the molded product is removed from the mold, there is a part of the molded product remaining on the mold surface, and if there is no remaining, it is considered good). ), and compared the elasticity immediately after demolding. Immediately after demolding, bend the molded product 180 degrees and measure the time it takes to stop cracking.
Green strength. The surface condition of the molded product, the filling length (mm) to the tip of the sheet divided by the total sheet weight (g) was defined as the liquid flow index (mm7g). The larger the value of the liquid flow index, the better the 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
A short strip (m x 15 cm) was fixed horizontally at a position 5 cm from one end and left in a constant temperature bath at 120°C for 1 hour. The heat resistance was compared.The surface condition of the molded product was visually observed, and whether it was a mirror surface or a linear surface was determined.

In addition, regarding the change over time, the resin solution (resin premix)
Changes in molding when left at ℃ for one day were observed.

Furthermore, the mold release effect was determined by the following method.

Using a high-pressure foaming machine NR-230 manufactured by Toho Kikai Co., Ltd., a wax-based mold release agent (Murikei B-712 manufactured by Chukyo Yushi Co., Ltd.) was applied in advance.
Spray the specified amount and set the temperature to 75℃.
, into a U-shaped mold with a height of 20 cm and a length of 40 c+n. After 50 seconds, the mold was opened to obtain a U-shaped molded product. Thereafter, the above-mentioned operation was repeated without applying an external mold release agent, and the number of times i at which demolding became impossible was determined.

Moreover, the evaluation of the painted product was performed as follows. The molded product was washed with Triclean steam for 30 seconds and then painted. (
Paint: Branit S manufactured by Dainippon Toyo Co., Ltd., baking temperature 100℃
30 minutes) The coated products were examined for paint sag by visual inspection and for adhesion of the paint film by a goblin test.

The above results are shown in Table 2.

Comparative Example 1 Dibutyl dilaurate and DABCO33L V (AirProducts
RIM molding was carried out in the same manner as in Example 1 with the same composition as in Example 1, except that the amount shown in Table 1 was used. Table 2 shows the moldability, physical properties of the molded product, number of demolding times, and surface condition.

Comparative Example 2 Except that a polyetheramine D-400 (TEXACO product) solution of zinc stearate (zinc stearate concentration 30 wt%) was used in the amount shown in Table 1 instead of internal mold release agent A as an internal mold release agent. had the same composition as in Example 1 and was RIM molded in the same manner. The results obtained are shown in Table 2.

Comparative Example 3 RIM molding was performed in exactly the same manner as in Example 1, except that no internal mold release agent was used. Second result
Shown in the table.

Comparing the results of Examples 1 to 4 in Table 2 with Comparative Examples 1 to 3, it is clear that the composition of the present invention has better molding performance than conventional compositions during polyurethane injection molding, and The obtained elastic body exhibits no deterioration in physical properties, no roughening of the surface, poor adhesion to paint, and no paint repellency or change over time.

Claims (2)

[Claims] (1) (a) Polyisocyanate (b) Polyether polyol having a molecular weight of 1,000 to 18,000 (c) 2,4-diamino-5-tert-butyltoluene, 2
, 6-diamino-3-tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene, and 2,3-diamino-4-tert-butyltoluene (d). A polyurethaneurea elastomer characterized in that a mixture containing a Bi fatty acid salt (e) an organic acid and (f) a free acid group and/or an internal mold release agent having a free acid base is reaction injection molded in a closed mold. manufacturing method. (2) A polyurethaneurea molded article obtained by the method of claim (1).