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WO1988000876A1 - Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule - Google Patents

Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule Download PDF

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Publication number
WO1988000876A1
WO1988000876A1 PCT/US1986/001581 US8601581W WO8800876A1 WO 1988000876 A1 WO1988000876 A1 WO 1988000876A1 US 8601581 W US8601581 W US 8601581W WO 8800876 A1 WO8800876 A1 WO 8800876A1
Authority
WO
WIPO (PCT)
Prior art keywords
mold
percent
weight
resin
primer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1986/001581
Other languages
English (en)
Inventor
Brian M. Kelly
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to PCT/US1986/001581 priority Critical patent/WO1988000876A1/fr
Priority to EP86905055A priority patent/EP0288457A1/fr
Priority to JP61504424A priority patent/JPH01500984A/ja
Publication of WO1988000876A1 publication Critical patent/WO1988000876A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
    • B29C37/0025—Applying surface layers, e.g. coatings, decorative layers, printed layers, to articles during shaping, e.g. in-mould printing
    • B29C37/0028—In-mould coating, e.g. by introducing the coating material into the mould after forming the article
    • B29C37/0032—In-mould coating, e.g. by introducing the coating material into the mould after forming the article the coating being applied upon the mould surface before introducing the moulding compound, e.g. applying a gelcoat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
    • B29C33/60—Releasing, lubricating or separating agents
    • B29C33/62—Releasing, lubricating or separating agents based on polymers or oligomers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
    • B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
    • B29C67/246—Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM]

Definitions

  • the present invention relates to article forming, and more particularly to methods and compositions useful for molding articles from plastic materials.
  • Injection molding is a well known method for the
  • the mold walls has been to coat the mold with a release agent, such as polymeric wax, silicone or other types of agents, prior to injection of the plastic.
  • a release agent such as polymeric wax, silicone or other types of agents
  • the formed plastic is baked to rigidify it 5 after the plastic has been removed from the mold. Subsequent to baking, a power wash is applied to the plastic to remove any residual release agent on the surface of the plastic.
  • This wash is required because the release agent 0 provides an insufficiently smooth or insufficiently conditioned surface for the application of paint to the plastic.
  • the plastic surface is then suitable for attachment of primer, and the plastic is primed using conventional spray or other equipment or by any other priming method known in the art.
  • the plastic is primed, it is given a bake to cure the primer. After the bake the surface generally is sanded and cleaned again. The 5 part is now in condition for receiving a topcoat, and the part is given another bake cycle to cure the topcoat.
  • the unremoved release agent couses a loss of adhesion between a subsequently applied primer and the substrate.
  • Conventional release agents are not suitable surfaces for adhesion of primer or topcoat to the surface of the article. This loss of adhesion often results in separation of the
  • the method of the present invention solves these and other problems by use of a primer that is preferentially adhered to the plastic, as compared to the metal mold, at injection or subinjection temperatures.
  • Injection temperatures for reaction injection molding (RIM) processes are typically on the order of 250°F.
  • the primer of the present invention has excellent adhesion to the plastic, and prevents the plastic from sticking to the mold. Therefore, no other mold release agent is needed in order to insure the free release of the formed plastic article from the mold. With no other mold release agent, there is no buildup that needs to be cleaned up, nor is there a need for a power wash to remove a release agent that isn't present.
  • the primer is also suitable for reception of a topcoat.
  • the primer is also suitable for reception of a topcoat.
  • the method permits consolidation of the baking requirements of the primer and topcoat, or the primer may require no more curing than that occurring during the molding operation.
  • the method thereby offers substantial savings of time and energy over prior molding methods.
  • an object of the present invention to provide an improved in-mold primer whereby a molded article may be easily and freely removed from the mold, thereby preventing sticking of the formed plastic article to the mold walls.
  • a further object of the present invention is to provide a primer for molded articles that is applied to the articles contemporaneously with the formation of the articles.
  • a still further object of the present invention is to provide a mold release agent that, during its use, leaves no residue on the mold surface.
  • a still further object of the present invention is to provide an in-mold primer for molded parts whereby the part can be topcoated after removal from the mold with little or no sanding of the part required.
  • Another object of the present invention is to provide a process for painting injection molded parts which consolidates the baking requirements of the primer and topcoat and thereby offers substantial savings of time and energy.
  • a further object of this invention is to provide an in-mold primer useful in a repeated molding process, which virtually if not completely eliminates cleaning of the mold between the molding of individual articles during a production run of upwards of ten thousand articles, yet which simultaneously provides a clean primed surface not requiring sanding prior to reception of a topcoat or finish coat.
  • a last object of this invention is to provide a primed, molded article whose surface mirrors the shape of the mold surface from which the article is molded, without any treatment of the article besides the use of a preferentially adhesive in-mold primer.
  • the invention as applied to injection molding of plastic parts is generally as follows: A coating of a type hereinafter described is applied to the interior walls of a mold by any method of application known in the art. The mold is then closed and a disparate plastic substrate is injected or otherwise inserted into the mold.
  • the plastic substrate is preferably a RIM plastic, which sets upon the reaction of two or more discreet components which are injected into the mold, advantageously admixed just prior to introduction into the mold.
  • the RIM plastic substrate is a polyurethane formed from a polyisocyanate component and a polyol component. Conventionally, as is well known in the art, a three to five per cent stoichiometric excess of polyisocyanate is employed.
  • the plastic substrate can also be a polyester or polyaramid resin.
  • the forming or fabrication process is then continued until completion, i.e., the part is formed.
  • the formed part is then removed from the mold and ready or nearly ready for application of the topcoat.
  • the part is then baked to cure the topcoat.
  • Many methods for applying a coating to the interior walls of a mold are known in the art. Such methods include manual or automatic spray (air or airless), powder coating, roller coating, curtain coating, continuous dry film application, flow coating and brushing.
  • Many methods for the introduction of a plastic substrate onto a mold surface are known in the art as well.
  • Forming or fabricating plastic parts by the mold process may take place at temperatures ranging from room temperature to 300°F.
  • the mold or die can be made from substrates which include wood, plastic and various metals, and can include plated substrates.
  • the coating need not be restricted to a primer and, in fact, can comprise a single-coat topcoat.
  • the coating comprises a primer.
  • the coating is characterized in that, at or below the temperature of formation of the plastic piece, it is strongly preferentially adherable to the plastic instead of the material constituting the surface of the mold.
  • the resin in the coating can be of the type found in the following list, but is not limited to: halogenated vinyl polymers; organic acids, esters and/or ethers of vinyl polymers; organic and inorganic acids, esters, and/or ethers of cellulose; or any of the above polymers further modified with functional groups such as, ( but not limited to: oxiranes; carboxyls; halogented alkyls, alkenyls, or alkynyls; hydroxyls; styrenyls; acryloyls; and the like.
  • Many resins typically used in the paint industry are usually undesirable for use as an in-mold primer, because they are designed to adhere to metal rather than preferentially adhering to the plastic part. These include polyesters, alkyd
  • the part may be removed from the mold by any method known in the art.
  • the part may be peeled from the mold, or may be manually removed from one side of a two piece mold; and, of course, many molds employ ejector pins to facilitate removal.
  • a primer according to the present invention advantageously comprises the above-described resin and any or all of a pigment, solvent, an acid scavenger, a plasticizer, a heat stabilizer and a wetting agent. 5
  • the functions of each additional constituent in a primer are, of course, known in the art.
  • a typical example of a formula for an in-mold primer suitable for use in the present invention is as follows, with the functions of the various components being as indicated: in Formula Percent by wt.
  • Epoxidixed Oil (Plasticizer and Acid Scavenger) .4
  • a resin, to be suitable for use in the present invention, must have relatively poor adhesion to metal and relatively good adhesion to organic substrates. 5
  • the composition given above, for example, has virtually no adhesion to metal mold surfaces at a temperature below 180°F.
  • the resin must also be durable enough to function in a primer.
  • One resin that meets these 0 criteria is VAGH, a hydroxylated vinyl chloride-vinyl acetate copolymer sold by Union Carbide.
  • the VAGH resin fulfills the above-mentioned characteristics and also has some hydroxyl functionality, which provides reactive sites for chemically bonding the primer to the 5 molded article. This hydroxyl functionality also provides a site at which an amino resin can crosslink vinyl copolymer to further enhance the durability of the primer.
  • the hydroxyl groups may also react with the excess polyisocyanate in the polyurethane substrate to enhance preferential adhesion of the resin to the substrate, instead of to the mold.
  • any resin with poor adhesion to metal can be used in the present invention, and the only limit on its adhesion to plastic depends upon the requirements of the end to which the primer will be put. Typical requirements are good ability to adhere to the plastic, good suitability for adhesion to a topcoat, and durability both during the painting process and in use of the product by the ultimate consumer.
  • the simplest way to determine the utility of a given resin for this purpose is to examine the technical specifications relating to adhesion (usually available, from the resin manufacturer) , and select and test those having the aforesaid characteristics and being otherwise suitable for the intended use.
  • compositions comprising about 10 to 15 percent by weight of resin, about 1 to 10 percent by weight pigment, about 0.1 to 1 percent by weight heat stabilizer, about 0.1 to 1 percent by weight wetting agent and solvent in a quantity sufficient to permit the application of the composition to the mold surface, are useful in the present invention.
  • the formulation of the example above is the most useful embodiment of the invention known to Applicant. The formulation has been successfully privately tested in molding automobile spare tire covers, automobile grille sections, automobile bumper fascia, automobile bumpers, automobile steering wheels. golf cart wheels, and wheel balancing machine cabinets.
  • the formulation was successfully applied in-mold to the following substrates for these articles, respectively: Dow Spectrim MM-363 and Ashland Arimax 1500; Dow Polyester; Mobay Bayflex 30; Mobay Bayflex 110-25; BASF Bayflex 28, Mobay Bayflex 28 IMR and Ottobock (West Germany) ; Dow 181 System; and Mobay Baydur 724, Mobay Bayflex 110-80 and Mobay Bayflex 110-50.
  • the formulation has also been successfully used as an in-mold primer on Mobay Bayflex 110-25 IMR.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
  • Paints Or Removers (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

Une couche d'apprêt utilisée à l'intérieur du moule et contenant une résine de préférence adhésive sert également simultanément d'agent de démoulage et permet d'obtenir des articles en plastique obtenus par moulage à injection par réaction (RIM) dont les surfaces reflètent virtuellement la surface du moule. Une telle couche d'apprêt ne laisse aucun résidu notable sur la surface du moule durant un cycle de production d'un grand nombre d'articles, le nettoyage du moule à chaque introduction d'un agent de démoulage traditionnel lors du moulage d'un article n'étant plus nécessaire. La résine préférée contenue dans la couche d'apprêt est un copolymère d'acétate de vinyle-chlorure de vinyle hydroxylé (résine VAGH).
PCT/US1986/001581 1986-08-04 1986-08-04 Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule Ceased WO1988000876A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/US1986/001581 WO1988000876A1 (fr) 1986-08-04 1986-08-04 Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule
EP86905055A EP0288457A1 (fr) 1986-08-04 1986-08-04 Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule
JP61504424A JPH01500984A (ja) 1986-08-04 1986-08-04 新しいプライマを用いた射出成形法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1986/001581 WO1988000876A1 (fr) 1986-08-04 1986-08-04 Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule

Publications (1)

Publication Number Publication Date
WO1988000876A1 true WO1988000876A1 (fr) 1988-02-11

Family

ID=22195587

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1986/001581 Ceased WO1988000876A1 (fr) 1986-08-04 1986-08-04 Procede de moulage par injection et couche d'appret amelioree utilisee a l'interieur du moule

Country Status (3)

Country Link
EP (1) EP0288457A1 (fr)
JP (1) JPH01500984A (fr)
WO (1) WO1988000876A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5035849A (en) * 1989-02-01 1991-07-30 Chisso Corporation Process for producing molded article using a releasing agent
US5536458A (en) * 1992-10-30 1996-07-16 Toyoda Gosei Co., Ltd. Method of molding two-color polyurethane parts by rim
US5628944A (en) * 1992-10-30 1997-05-13 Toyoda Gosei Co., Ltd. Method and apparatus for molding two-color polyurethane parts by RIM
US5849537A (en) * 1989-09-19 1998-12-15 Miller Brewing Company Method of expressing antifreeze proteins in yeast
WO2017131742A1 (fr) * 2016-01-29 2017-08-03 Compagnie Generale Des Etablissements Michelin Lubrifiant de moule électroconducteur pour des bandages non pneumatiques

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1889905A (en) * 1930-02-17 1932-12-06 Jr Charles Marshall Saeger Core or mold binder, coating or paste
SU383608A1 (ru) * 1971-10-19 1973-05-23 Антиадгезионный разделительный состав
US4285897A (en) * 1979-01-11 1981-08-25 Nalco Chemical Company Water-based anti-blemish paint
US4312672A (en) * 1979-04-25 1982-01-26 Metzeler Kautschuk Gmbh Release agent for removing plastics, especially polyurethane plastics from molds
GB2079667A (en) * 1980-07-10 1982-01-27 Itt Plastic moulded part
US4592887A (en) * 1981-04-30 1986-06-03 Kuraray Co., Ltd. Method of producing shaped resinous articles

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2123074B1 (fr) * 1970-11-05 1973-12-28 Progil Bayer Ugine
GB2068819A (en) * 1980-02-13 1981-08-19 Exxon Research Engineering Co Polyurethane mouldings

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1889905A (en) * 1930-02-17 1932-12-06 Jr Charles Marshall Saeger Core or mold binder, coating or paste
SU383608A1 (ru) * 1971-10-19 1973-05-23 Антиадгезионный разделительный состав
US4285897A (en) * 1979-01-11 1981-08-25 Nalco Chemical Company Water-based anti-blemish paint
US4312672A (en) * 1979-04-25 1982-01-26 Metzeler Kautschuk Gmbh Release agent for removing plastics, especially polyurethane plastics from molds
GB2079667A (en) * 1980-07-10 1982-01-27 Itt Plastic moulded part
US4592887A (en) * 1981-04-30 1986-06-03 Kuraray Co., Ltd. Method of producing shaped resinous articles

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0288457A4 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5035849A (en) * 1989-02-01 1991-07-30 Chisso Corporation Process for producing molded article using a releasing agent
US5849537A (en) * 1989-09-19 1998-12-15 Miller Brewing Company Method of expressing antifreeze proteins in yeast
US5928877A (en) * 1989-09-19 1999-07-27 Miller Brewing Company Assay for an antifreeze protein
US5536458A (en) * 1992-10-30 1996-07-16 Toyoda Gosei Co., Ltd. Method of molding two-color polyurethane parts by rim
US5628944A (en) * 1992-10-30 1997-05-13 Toyoda Gosei Co., Ltd. Method and apparatus for molding two-color polyurethane parts by RIM
WO2017131742A1 (fr) * 2016-01-29 2017-08-03 Compagnie Generale Des Etablissements Michelin Lubrifiant de moule électroconducteur pour des bandages non pneumatiques
CN108883660A (zh) * 2016-01-29 2018-11-23 米其林集团总公司 用于非充气轮胎的导电脱模剂
CN108883660B (zh) * 2016-01-29 2022-03-11 米其林集团总公司 用于非充气轮胎的导电脱模剂

Also Published As

Publication number Publication date
JPH01500984A (ja) 1989-04-06
EP0288457A4 (fr) 1988-08-23
EP0288457A1 (fr) 1988-11-02

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