US005633289A United States Patent (19) 11 Patent Number: 5,633,289 Nakamura et al. 45) Date of Patent: May 27, 1997 54 PROCESS FOR MOLDING AN INTEGRAL FOREIGN PATENT DOCUMENTS SKN FOAMAND A POLYURETHANE 0006381 1/1980 European Pat. Off.. MATERAL FOR MOLDING THE SAME 0044226 1/1982 European Pat. Off.. 75 Inventors: Michihiko Nakamura; Masanao 0211495 2/1987 European Pat. Off.. Ishikake; Yukio Kawakita; Akira 0353061 1/1990 European Pat. Off.. Mabuchi; Osamu Yamanaka, all of (List continued on next page.) Aichi-ken, Japan OTHER PUBLICATIONS 73) Assignee: Toyoda Gosei Co., Ltd., Nishikasugai, Patent Abstracts of Japan, vol. 5, No. 190 (M-100) (1981). Japan Patent Abstracts of Japan, vol. 8, No. 057 (M-283) (1984). Patent Abstracts of Japan, vol. 4, No. 105 (M-023) (1980). Patent Abstracts of Japan, vol. 88, No. 1007 (M-750) (21) Appl. No.: 213,014 (1988). 22 Filed: Mar 14, 1994 Primary Examiner-Nathan M. Nutter (30) Foreign Application Priority Data Assistant Examiner-Duc Truong Attorney, Agent, or Firm-Cushman Darby & Cushman Mar 16, 1993 JP Japan .................................... 5-082660 Intellectual Property Group of Pillsbury Madison & Sutro, Mar 16, 1993 JP Japan .................................... 5-082661 LLP I51 int. Cl. ... C08J 9/34 57 ABSTRACT (52 U.S. Cl. ........................... 521/51; 521/159; 521/170; A process and a polyurethane material for molding a semi 521/174; 521/176; 528/48: 264/51 rigid integral skin foam which comprising an integral skin (58) Field of Search .............................. 521/51, 159, 170, having a low degree of foaming and a core having a high 521/174, 176; 264/51; 528/48 degree of foaming. The process includes evacuating a mold 56) References Cited cavity to reduce the pressure thereof below atmospheric pressure; injecting into the evacuated mold cavity a poly U.S. PATENT DOCUMENTS urethane material; and foaming the material to fill the cavity. 3,824,199 7/1974 Nadeau et al.. The polyurethane material contains a polyol component and 3,954,537 5/1976 After et al.. an isocyanate component with, at most, 5 parts by weight of 3,970,732 7/1976 Slaats et al. a solvent for 100 parts by weight of the polyol component, 4,042,540 8/1977 Lammerting et al.. in the absence of freon. (List continued on next page.) 11 Claims, 17 Drawing Sheets 22 ZZZZZZZZZZZZZZZZZZ 5,633,289 Page 2 U.S. PATENT DOCUMENTS FOREIGN PATENT DOCUMENTS 4,206,170 6/1980 Sassaman et al. o: 8: E.uropean EasPat. Off.3. 4285,893 8/1981 Contastin. 0461522 12/1991 European Pat. Off.. 4,347,330 8/1982 Demou et al. 0534358 3/1993 European Pat. Off.. 4,379,105 4/1983 Taylor et al.. 1575243 7/1969 France. 4,510,106 4/1985 Hirsch. 2634,157 1/1990 France. 4,517,313 5/1985 Nakatani. 2318794 4/1973 Germany. 4,555,087 11/1985 Wallner et al.. 2212609 1943, Germany. 4,572,865 2/1986 Glucket al.. ... g: &M 4,579,700 4/1986 Cavender. 4115456 11/1992 Germany. 4,909,972 3/1990 Britz. 55-63237 5/1980 Japan. 4,916,168 4/1990 Pham et al. 55-63238 5/1980 Japan. 4,988,271 1/1991 Kumasaka et al.. 56-111648 9/1981 Japan. 5,100,926 3/1992 Kondo et al.. 62-164709 7/1987 Japan. 63-268624 1/1988 Japan. 5,132,329 7/1992 Lynch et al.. 1407244 9/1975 United Kingdom. 5,166,183 11/1992 Franyutti et al. 2092509 8/1982 United Kingdom. U.S. Patent May 27, 1997 Sheet 1 of 17 5,633.289 ZZZZZZZZZZZZZZZZZZAN 2 U.S. Patent May 27, 1997 Sheet 2 of 17 5,633.289 FIG.2 U.S. Patent May 27, 1997 Sheet 3 of 17 5,633,289 FIG.3 U.S. Patent May 27, 1997 Sheet 4 of 17 5,633.289 FIG. 4. N U.S. Patent May 27, 1997 Sheet 5 of 17 5,633.289 FIG.5 U.S. Patent May 27, 1997 Sheet 6 of 17 5,633.289 FIG.7 N pe NT 38 3a KS (3)\ É R réUN Z s 2. N ZZZZZZZZZZZZZZZZZZ U.S. Patent May 27, 1997 Sheet 7 of 17 5,633,289 U.S. Patent May 27, 1997 Sheet 8 of 17 5,633.289 U.S. Patent May 27, 1997 Sheet 9 of 17 5,633,289 U.S. Patent May 27, 1997 Sheet 10 of 17 5,633,289 U.S. Patent May 27, 1997 Sheet 11 of 17 5,633.289 U.S. Patent May 27, 1997 Sheet 12 of 17 5,633.289 FIG.28 72 70 68 66 64 62 60 58 56 54 52 50 O 100 200 300 400 500 Vacuum degree of ca v i t y (To r r) U.S. Patent May 27, 1997 Sheet 13 of 17 5,633,289 C FIG. 29 --9 80 - N 4 O O. : Comparative A. example > 3 5 O. : Example 5 --a N-1 A: Example 6 CO D: Example 7 30 C) to rum 2 5 CO C) 2 O - O 1 O 2 0 3 O 4 0 5 0 Amount of Ino no hydric a l cohol (parts by we ight) 210 200 190 : Core...ive s 180 O: Example 5 A: Example 6 O 170 : Example 7 e - 160 y 150 b0 140 130 ?t 120 110 100 O 1. 2 3 4 5 Amount of mo no hydric a l cohol (parts by weight) U.S. Patent May 27, 1997 Sheet 14 of 17 5,633.289 FIG.3 ? 11 /////////// (f 12 N 3 al N. N. PZZZZZZZZZZZZZ,N U.S. Patent May 27, 1997 Sheet 15 of 17 5,633.289 FIG. 32 . *"ZZZZZZZZZZZZZ N 12 XXXI 1447 4 U.S. Patent May 27, 1997 Sheet 16 of 17 5,633.289 FIG.33 11 Y/////////////////// 12 - U.S. Patent May 27, 1997 Sheet 17 of 17 5,633.289 FIG.35 21 9 5 46 7 ZZZZZZZZZZX2/7ZZ 4 - 777 PE 2,33 SSSNN. 4 M 5,633.289 1. 2 PROCESS FORMOLDING AN INTEGRAL freon release to the atmosphere from any industrial or SKN FOAMAND A POLYURETHANE commercial process is recognized as a global problem and MATERAL FOR MOLDING THE SAME reductions in its use are being mandated by many countries; BACKGROUND OF THE INVENTION formation of the integral skin by collapsing bubbles at the The present invention is further detailed in Japanese surface section by the internal foaming pressure allows Patent Application Nos. 5-82660 and 5-82661, both filed minute bubbles to inevitably remain in the skin which Mar. 16, 1993, for which the present application claims ultimately impair the appearance of the final foamed prod priority and the entire contents of which are incorporated uct; and overpacking and subsequent discharge of the poly herein by reference. urethane material from a vent is necessary to increase the 1. Field of the Invention 10 internal foaming pressure and to promote the mold filling. The present invention provides a process for molding a Ultimately this leads to a great loss of material. semi-rigid integral skin foam, wherein the semi-rigid inte An effective way of increasing the production efficiency gral skin foam comprises an integral skin region having a of producing urethane foam articles is to increase the low degree of foaming and a core region having a high reaction rate of the polyurethane material, thereby reducing degree of foaming. The present invention further provides a 15 the cure time. This object can be achieved by increasing the polyurethane material for molding such a foam, which is amount of the catalyst or raising the temperature of the suitable for reaction injection molding (RIM) of a molded polyurethane material before injection. The latter is prefer product having an integral skin foam, such as a cover or pad able to the former, which leads to an increase in production for a steering wheel of a motor vehicle, an instrument panel, cost. It has, however, been actually impossible to adopt the a console box lid, a glove box lid, a headrest, an armrest, or 20 latter method when freon is used as a foaming agent, since an air spoiler. its vaporization or a rise in tank pressure is likely to occur 2. Description of Related Art immediately after the injection of the polyurethane material. A semi-rigid polyurethane foam containing an integral Moreover, the use of freon in a large amount can delay the skin region having a low degree of foaming on its surface curing of the product of the urethane-forming reaction and and a core region having a high degree of foaming at its 25 thereby prolong the cure time, as the heat of the urethane center is generally referred to as an integral skinfoam (ISF). forming reaction is dissipated due to vaporization of the An ISF is produced from a long-chain polyol having a freon. By eliminating freon in the urethane-forming molecular weight of the order of thousands, such as 1,000-9, reaction, the present invention provides greater alternatives 000, a low-molecular polyol having a molecular weight of in this regard. the order of tens to hundreds such as 10-900, a catalyst, a 30 Further, freon foamed processes which include a core in pigment, freon as a foaming agent, and an isocyanate the mold cavity, such as is common in the production of component. In normal operations, all the components, steering wheels, suffer from turbulence induced defects such except the isocyanate component, are preliminarily mixed to as pinholes, voids and short shot, due to entrapped air.