JPS6015418A - Improvement of property of polyurethane molding - Google Patents

Abstract

PURPOSE:To form a polyurethane molding excellent in weather resistance and suitable for use in automobile exterior trims, by reacting a specified polyether- polyol with a specified organic polyisocyanate prepolymer. CONSTITUTION:Use is made of a prepolymer (NCO group content of about 10- 35wt%) formed by reacting an organic polyisocyanate (e.g., 2,4-tolylene diisocyanate) with a polyol ester of ricinoleic acid obtained by reacting ricinoleic acid with a dihydric or trichydric polyol (e.g., mono- or di-ricinoleic acid ester of polyoxypropylene diol obtained by addition-polymerizing ethylene glycol with propylene oxide). Namely, the above prepolymer is reacted with a polyether- polyol obtained by addition-polymerizing a mixture of ethylene oxide and propylene oxide at a molar ratio of about 10:90-30:70 with a polyalcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the physical properties of polyurethane molded articles.

Compared to other synthetic rubbers, polyurethane has higher tear strength and tensile strength, as well as superior abrasion and oil resistance, so it has traditionally been used in industrial parts such as crystals, belts, seals, and gaskets. .

The recent development of reaction injection molding (RIM) technology has enabled the mass production of large polyurethane molded articles. In particular, microcellular urethane elastomer molded products have come to be used in large quantities for automobile exterior parts such as pan bars, fascia, and spoilers, and their excellent impact absorption performance contributes to improved safety, and they are lighter than metal. Therefore, the effect of reducing fuel consumption is significant.

On the other hand, polyurethane does not have strong water resistance or heat resistance, so if it is exposed to wind and rain for a long period of time or exposed to sunlight in the summer, the molded product may warp or expand, as it does not have strong water or heat resistance. Deformation occurs, making it difficult to use. In addition, in order to further reduce the weight of automobiles and save on fuel consumption, there is a desire to reduce the wall thickness of these exterior parts, but reducing the wall thickness will encourage deformation such as warping. As a result of various studies to solve these problems, the present inventors discovered that ricinoleic acid ester is effective and arrived at the present invention.

That is, the present invention, when producing a polyurethane molded product by reacting a polyol and a polyincyanate, (1) a polyether polyol obtained by addition polymerizing ethylene oxide and propylene oxide to a multi-fllfi alcohol; (2) A method for improving the physical properties of a polyurethane molded article, which is characterized by reacting a prepolymer obtained by reacting a heptanomonic acid ester of a polyol with an organic polyisocyanate.

Examples of the polyhydric alcohol used in the present invention include ethylene glycol, phlopylene gellicol, diethylene glycol, trimethylene glycol, butanediol, cyclohexanediol, glycerin, hexanetriol,
Trimethylolpropane, pentaerythritol, nruvit, sucrose, novolak resin, citanolamine, triethano-Δ monoluamine, tripropaturamine, N-N-N'.
N'-tetrahydroxyethylethylenediamine, methylenebis(N,・N-dihydroxyethylaniline),
N-N-N'.N/-tetrahydroxyethyltolylenediamine, etc. The appropriate molar ratio of ethylene oxide and propylene oxide to be addition-polymerized to these polyhydric alcohols is 10:90 to 30:0. If the ratio of ethylene oxide is lower than this range, the reactivity of the polyether polyol will be reduced, and if it is higher than this range, the water resistance of the polyurethane will be reduced.

The polyether polyol used in the present invention has an OH value of 20
~60 is preferred. If the OH value is lower than this range, the reactivity of the polyether polyol will decrease, and if it is higher than this range, the buffering performance of the polyurethane will decrease. These polyether polyols can be used alone or in combination with other polyols such as polybutadiene polyols, polyester polyols, polycaprolactone polyols, polytetramethylene ether polyols, polymer polyols, and the like.

In the present invention, the polyol constituting the ester with ricinoleic acid is suitably divalent or trivalent, and a compound in which all or a part of the OH groups of the polyol is esterified with ricinoleic acid is used.

Examples of these polyols include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, siglopylene glycol, triethylene glycol, tripropylene glycol, bisadipate (glopylene glycol ester), bisadipate (diglobylene glycol ester), etc. ), adipic acid
Diethylene glycol polyester diol, glycerin.

It is a polyoxyalkylene diol or a polyoxyalkylene triol obtained by addition polymerizing trimethylolpropane, etc., and an alkylene oxide such as ethylene oxide or propylene oxide to these polyols.

Among the polyol esters of 7-nolic acid used in the present invention, particularly preferred compounds include, for example, mono- or di-ricinoleic acid of polyoxypropylene diol obtained by addition polymerization of propylene oxide to ethylene glycol. esters, mono- or di-ricinoleic acid esters of polyoxyalkylene diol obtained by the cross-polymerization of ethylene oxide and propylene oxide to propylene gellicol, and polyoxylic acid obtained by addition polymerization of propylene oxide to glycerin. These include mono-, di-, or tri-ricinoleic acid esters of fluoropyrene triol, mono- or di-ricinoleic acid esters of adipic acid/diethylene glycol polyester diol, etc. The preferred range of the OH value is 30 to 200, and especially 40-150 is preferable.

The organic polyisocyanate used in the present invention is, for example, 2
・4-Tolylene diisocyanate, 2,6-to(MDI)
), naphthalene-1,5-diisocyanate (NDI)
, 3,3'-dimethyl-4,41-biphenylene diisocyanate) (TODI), xylylene diisocyanate) (XDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), inphorone diisocyanate ) (IPDI), hexamethylene diisocyanate (HDI), hydrogenated xylylene diisocyanate (l
(XDI), crude TDI.

Polymethylene polyphenylisocyanate (crude MD
I), and incyanurate modified products, carbodiimidized modified products, biuret modified products, etc. of these isocyanates.

The prepolymer used in the present invention is produced by reacting a ricinoleic acid ester of a polyol and an organic polyisocyanate at 80-120° C. for several hours while stirring in a nitrogen stream. The ratio of raw materials is adjusted so that the obtained prepolymer has an NCO group weight content of 0 to 35% by weight.

The prepolymer may be used alone or in combination with other organic polyisocyanates.

The amount used is such that the equivalent ratio of the total amount of NGO groups contained in the prepolymer and organic polyisocyanate to the total amount of active hydrogen contained in the polyether polyol and the crosslinking agent and blowing agent described below is 0.95 to Make it 1.15.

The appropriate amount of Nisdel ricinoleate used as a polyol is 5 to 20% by weight based on the total amount of urethane raw materials.

In the present invention, a crosslinking agent is usually used in order to shorten the reaction time and improve the physical properties of the molded product.

Preferred compounds as crosslinking agents include polyhydric alcohols such as ethylene glycol, phlopylene gellicol, diethylene fIJ col, dipropylene glycol, glycerin, hexanetriol, trimethylolpropane, pentaerythritol, diglycerin, and these polyhydric alcohols. It is a low-molecular polyol with 1 to 2 moles of ethylene oxide added to it. For example, aminoaltools such as monoethanolamine, jetanolamine, triethanolamine, motuprobanolamine, dibrobanolamine, and tripropaturamine can also be used as crosslinking agents.Crosslinking agents can be used alone or in combination of two or more. The amount used is 10 parts by weight of polyether polyol.
~30 parts by weight is preferred.

Known urethanization catalysts can be used in carrying out the present invention. One type of catalyst or a mixture of two or more types may be used. Among these catalysts, examples of tertiary amines include triethylamine, tripropylamine, triimpropaturamine, tributylamine, trioctylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N- Octadecylmol 7-olin, monoethanolamine, jetanolamine, triethanolamine, N-methyljetanolamine, N,N-dimethylethanolamine, diethylenetriamine, N, N, N', N'-tetramethylethylenediamine, N, N, N', N/-tetramethylpropylenediamine, N, N, N', N/
-tetramethylbutanediamine, N, N, N',
N'-tetramethyl-1,3-butanediamine, N,
N, N'.

N/-tetramethylhexamethylenediamine, bis('
2-(N, N-dimethylamino)ethyl]ether,
N,N-dimethylbenzylamine, N,N-dimethylbenzizylamine, N,N-dimethylcyclohexylamine, N, N, N', N'', N〃-pentamethyldiethylenetriamine, triethylenediamine, formate of triethylenediamine and other salts, amino group oxyalkylene adducts of primary and secondary amines, more azacyclic compounds of N,N-dialkylpiperazines, various N,N
', N''-trialkylamine alkylhexahydrotriazines, β-aminocarbonyl catalyst disclosed in Japanese Patent Publication No. 52-43517, β-aminonitrile catalyst disclosed in Japanese Patent Publication No. 53-14279, and the like.

Examples of organometallic urethanation catalysts include tin acetate, tin octoate, tin oleate, tin laurate, dibutyltin diacetate, diptyltin dilaurate, dibutyltin dichloride, lead octoate, and lead naphthenate.

Further, as a blowing agent, water, trichloromonofluoromethane, methylene chloride, pentane, hekisho, etc. are used.

Furthermore, foam stabilizers, colorants, flame retardants, fillers, antioxidants, ultraviolet absorbers, ultraviolet stabilizers, and the like may be added as necessary.

To apply the present invention, a polyether polyol, a crosslinking agent, a catalyst, a blowing agent, a coloring agent, etc. are mixed to form a liquid A.

Separately, a prepolymer is prepared by heating and reacting ricinoleic acid ester and an organic polyinsyanate in a nitrogen stream for several hours, which is used as liquid B. If necessary, an organic polyisocyanate is further added and mixed to this prepolymer to prepare a B solution.

Liquid A and liquid B are rapidly mixed at a predetermined ratio and immediately poured into a mold preheated to 60 to 70°C. After being left in the mold for several minutes, the solidified polyurethane molding is removed from the mold.

The resulting polyurethane molded product has a bending modulus of 2000
~4000 kS'/cm''i, has strong durability against wind and rain, and does not sag even when the temperature rises due to sunlight irradiation in the summer, so it can be used for a long period of time as an exterior product for automobiles and the like.

Furthermore, it is possible to improve these problems and at the same time reduce the weight by reducing the thickness of the parts.

K, which measures the water resistance of a molded product, is the rate of dimensional change in the vertical and horizontal directions after immersing the molded product in water at 40°C for 10 days.
2) was measured and the average value is shown.

To measure deflection due to heat, use a length of 15 cm.

A plate-shaped test piece with a width of 3 cm was fixed and held horizontally up to 5 cm from one end, and after being left in an air bath at 120° C. for 1 hour, the displacement of the other end is shown as sagging.

Representative examples according to the present invention are shown below.

Example 1 Cree-1! 60 parts by weight of a polyether polyol with an OH number of 24 obtained by addition polymerization of propylene oxide and ethylene oxide (molar ratio 5/1) to chrycerin, propylene oxide and ethylene oxide (molar ratio 4/1) to chrycerin, tl- 40 parts of a polyether polyol with an OH number of 54 obtained by addition polymerization, 0.04 parts by weight of ethylene glycol meth as a cross-linking agent, and 0.04 parts by weight of diptyltin dilaurate as a catalyst were mixed to form a liquid A, and then a liquid B was used for the next preparatory step. The polymer was synthesized.

Prepolymer (1) After reacting 342 parts by weight of polyoxypropylene polyoxyethylene diol silicinoleate (OHHSO 342 parts by weight with 72 parts by weight of diphenylmethane-4,4'-diisocyanate at 90°C for 3 hours, the NCO group weight content A prepolymer having an NCO group content of 20.0% by weight and obtained by adding 8 parts by weight of 29% by weight difluoromethane-4.4/-diisocyanate.

Both liquids A and B were mixed, poured into a mold, left for 5 minutes, removed from the mold, and the physical properties of the obtained molded article were as shown in Table 1.

Example 2 A liquid A similar to that in Example 1 was prepared, and the following prepolymer was synthesized as a liquid B.

Prepolymer (2) 20 parts by weight of monoricinoleic acid ester of polyoxypropylene diol (OH value 110), diphenylmethane-
NCO group content 19 obtained by heating and reacting 24 parts by weight of 4,4'-diisocyanate and 56 parts by weight of modified diphenylmethane-4,4'-diisocyanate having an NCO group content of 29 weight 2 at 90°C for 3 hours. wt% prepolymer.

Both liquids A and B were mixed, poured into a mold, allowed to stand for 5 minutes, and then removed from the mold. The physical properties of the molded article obtained were as shown in Table 1.

Reference Example 1 The same liquid A as in Example 1 was used, and as liquid B, 95.6 parts by weight of modified diphenylmethane-4,4'-diinthioate having an NCO group content of 29% was used.

After mixing both solutions A and B, they were treated in the same manner as in Example 1, and the results obtained were as shown in Table 1.

It is clear from Table 1 that the use of ricinoleic acid ester reduces the dimensional change rate and thermal deflection of polyurethane molded articles.

Table 1 Density (f/cm') 0.91 0.89 0.90
0.8 0.6 1.2 Heat deflection (mm)
) 7゜1 5.4 8.7 Example 3 85 parts by weight of a polyether polyol with an OH value of 28 obtained by addition polymerization of propylene oxide and ethylene oxide (molar ratio ss/15) to pentaerythritol, propylene to glycerin 15 parts by weight of a polyether polyol with an OH number of 28 obtained by addition polymerization of oxide and ethylene oxide (mole ratio 60/40), 27 parts of ethylene glycol as a crosslinking agent, 0.5 parts by weight of triethylenediamine as a catalyst, and diptyltin dilauret. ) and 4 parts by weight of trichloromonofluoromethane as a blowing agent were mixed to prepare a liquid A.

Separately, 84 parts by weight of NCO group-containing 29% by weight diphenylmethane-4,4'-diincyanate and silicinoleic acid ester of polyoxypropylene diol (OH
A prepolymer containing 23 weight NCO groups obtained by reacting 316 parts by weight of HSO at 90° C. in a nitrogen stream for 3 hours was used as liquid B.

Using a RIM high-pressure injection molding machine, the flow ratio of liquid A and liquid B was adjusted to a weight ratio of 100 to 130 (NGO10H equivalent ratio was 1.05).
) was injected into a mold heated to 60°C, and the molded product was taken out after being left for 5 minutes.

As a molded product, length 30 cm, width 29 cm, thickness 2
・5mm s 3.0 mm, 4.0 mm and 5
．． A 0 mm plate was created.

The densities of these plates were as follows:

Thickness (mm) 2.5 3.0 4.0 5.0 Density (
f/cm”) 1.08 1.07 1.07 1.0
7 In addition, these plate-like test pieces were taken and the bending modulus, water resistance, and thermal deflection were measured, and the results were as shown in FIGS. 1, 2, and 3.

Reference Example 2 In Example 3, NC was used instead of the prepolymer as liquid B.
Modified diphenylmethane-4,4 with O group content 29 wt.
/- diisocyanate, and the flow ratio of A liquid and B liquid was set to 100:107 weight ratio (NGO10H equivalent ratio is 1.05
) and processed in the same manner as in Example 3 to produce a plate.

The densities of these plates were as follows:

Thickness (mm) 2.5 3.0 4.0 5.0 Density (
f/cm3) 1.06 1.08 1.06 1.0
7 In addition, test pieces were taken from these plates and the bending modulus, water resistance, and thermal deflection were measured, and the results were too small as shown in FIGS. 1, 2, and 3.

Figure 1 shows the case where ricinoleic acid ester prepolymer is used as liquid B and the case where modified diphenylmethane is used as liquid B.
A bending modulus almost equivalent to that obtained when 4,4'-diisocyanate was used was obtained.

However, polyurethane using a prepolymer of ricinoleic acid ester had low water resistance dimensional change rate and thermal deflection, as shown in FIGS. 2 and 3.

In addition, these two physical properties are the same as that of modified diphenylmethane-4゜4'-
Rather than a 5 mm thick plate using diisocyanate, a 3 mm thick plate using silinolate prepolymer.
The 5mm plate was better. That is, it is possible to improve physical properties and reduce weight at the same time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between bending modulus and sample thickness, FIG. 2 is a diagram showing the relationship between water resistance (dimensional change rate) and sample thickness, and FIG. 3 is a diagram showing the relationship between thermal deflection and sample thickness. Patent applicant Mitsui Nisso Urethane Co., Ltd.

Claims (1)

[Claims] When producing a polyurethane molded product by reacting a polyol and a polyisocyanate, (1) a polyether polyol obtained by addition polymerizing ethylene oxide and propylene oxide to a polyhydric alcohol; 2) A method for improving the physical properties of a polyurethane molded article, which comprises reacting a prepolymer 1 obtained by reacting a ricinoleic acid ester of a polyol with an organic polyisocyanate.