JPH0737037B2 - Method of molding a product from a curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to methods for providing color contrast regions on a molded article and compositions for providing color contrast. The composition forms a second body which forms the body of the product.
In a mold for molding a product by curing the composition of, applied to a predetermined area of the mold surface,
This causes the contrasted areas on the mold surface to become integral with the cured product during curing of the second composition.

European Patent Publication 61245 describes a method of molding a molded article having a color contrast area in a desired portion of the molded article, the contrast area comprising at least one finely divided filler in the mold portion. It is provided by coating with a composition comprising a mixture with at least one finely divided pigment. Preferably, the mixture is applied as a suspension in a liquid carrier that readily volatilizes at mold filling temperatures, generally above 50 ° C. The weight ratio of filler to pigment is in the range of 1: 1 to 100: 1, preferably 5: 1 to 50: 1.

Although this procedure has been widely used for molding sanitary ware products with color contrast from curable, highly filled methylmethacrylate compositions since this method was used commercially, satisfactory results have been obtained. Care must be taken to gain. The reason is that the finished product has a surface with an unattractive appearance, mainly because the coating shifts from the application area during the subsequent filling and curing process, causing scratches or discontinuities in the contrast-colored areas of the surface. Will be.

The present invention provides a method that provides a more reliable means of obtaining molded articles having areas of color contrast.

According to the method of the present invention, a formed article having a color contrast region on the surface of a product is a method of curing a curable composition between corresponding mold parts, and the mold parts are kept at a temperature rise. While applying a coloring composition to at least one predetermined area of the mold part, closing the mold part to form a mold cavity, and curing the composition in the cavity. The method comprises a liquid carrier, wherein the coloring composition comprises (a) a mixture of 0 to 100 parts by weight of a polymerizable liquid and a corresponding 100 to 0 parts by weight of a non-polymerizable volatile organic solvent, (b) a total composition. 0.1-10% by weight of an inorganic pigmented colorant or 0.0001-1% by weight of an organic pigment or dye, (c) 0-60% by weight of the synthetic composition, having an average particle size of less than 5 microns. Ground filler, (d) 0.1-50% by weight, liquid Soluble in carrier,
A dry oil-modified alkyd resin, and (e) a preform polymer soluble in a liquid carrier, present in a concentration of at least half the concentration of the dry oil-modified alkyd resin, comprising components (a), (b), (c) , (D) and (e) total 100% and (a) is present in a concentration of at least 25% by weight of the total composition.

Molded articles that can be produced according to the method of the present invention,
Includes sanitary ware products, especially integral kitchen sink tops that include a drainage surface as part of the sink top. Color contrast is typically imparted to specific areas of the product, such as the drainage area of the sink and the surrounding rim. However, the composition of the invention may be applied to the entire exposed surface of the molded part. In this case, the color contrast is achieved by applying different colors of the coloring composition according to the invention in the predetermined areas of the mold, which composition is transferred to the molded article during molding. Let's do it.

It is not essential for the composition to include a finely divided filler, but when present it is preferred to make up at least 5% by weight of the total composition, desirably at least 20%. When present, the finely divided filler is 1: 1 to 100: 1, preferably 5: 1, based on the weight ratio of filler to pigment.
It should be present in the range of ~ 50: 1. If the colorant is an organic pigment or dye alone, the ratio of filler (if present) to colorant will generally be greater than 100: 1.

Throughout this specification the term "pigment" means an insoluble material added to a composition for the purpose of controlling the color of the composition. The term "filler" means an insoluble material added to a composition for the purpose of altering the physical properties of the composition other than its color.

Typical inorganic pigments are highly pigmented materials such as transparent iron oxides. Examples of organic pigments are phthalocyanines, quinacridones and endanthrons. Examples of organic dyes are anthraquinones, monoazo and diazo dyes and perinones.

Typical fillers are described in British Patent Specification 1493393 in connection with their use in liquid curable compositions.
They include silica derived from quartz, cristobalite or phosphosilicate, alumina including hydrated alumina, calcined and uncalcined kaolin and feldspar. In said patent specification, a suitable filler particle size is such that at least 95% of the number of filler particles has a size smaller than 10 microns and no particle size above 100 microns is present. It is prescribed. For the purposes of the present invention, the filler particles, when present, are smaller than 5 microns.
It should preferably have an average size of less than 3 microns.

Dry oil modified alkyd resins are produced by the interaction of at least three materials: a dibasic acid, a polyhydric alcohol and a dry oil fatty acid or an alcoholized dry oil. These resins may also be prepared by direct esterification of drying oil fatty acids with dibasic acids and polyhydric alcohols or by direct esterification of drying oils first with polyhydric alcohols and then etherification with dibasic acids. Good. In the reaction mixture, monocarboxylic acids, for example, benzoic acid,
Alternatively, other modifiers such as phenolic resins may be present.

The proportion of drying oil may be as low as 20% and as high as 80% or higher in the final resin. A resin having a solid content at the lower limit of this range is preferable. The number average molecular weight of the alkyd is preferably in the range of 1000 to 5000.

Dry oil acids are preferably naturally occurring vegetable or marine oils,
For example, it is preferably derived from flaxseed oil, corn oil, castor oil, tung oil, tall oil and rosin.
The unsaturated acids of these oils may be complexed or uncomplexed and can be used as monomers, dimers or trimers. Preferred acids have an iodine value of about 120-300 and include linoleic acid, isolinoleic acid, linolenic acid, eleostearic acid and abietic acid. The mixed acids of natural oils are readily produced by a technique known as pressure cracking and are the preferred starting materials. Therefore, dehydrated castor oil fatty acid, linseed oil fatty acid, soybean fatty acid, tung oil fatty acid, rosin acid and tall oil acid can be used.

Preferred polyhydric alcohols, C ₂ -C ₆ aliphatic polyols containing from 2 to 6 hydroxy groups, for example, ethylene glycol, glycerol, pentaerythritol and mannitol. It is also possible to use mixtures of polyols.

Dibasic acids that can be used alone or with other dibasic acids include phthalic acid, phthalic anhydride, isophthalic acid,
Terephthalic acid (preferably used in a mixture), including adipic acid and other C ₄ -C ₁₂ saturated aliphatic dicarboxylic acids.

Although the liquid carrier for the composition need not include a polymerizable liquid, it is preferred that at least 5 parts per 100 parts by weight of carrier be a polymerizable liquid having a boiling point below 150 ° C. The polymerizable liquid is preferably chosen to be the same as or copolymerizable with the polymerizable material of the composition which is cured in the mold to form the body of the molded article. If the body of the molded article is to be formed from a curable composition based on methyl methacrylate, the polymerizable material of the color contrast product of the present invention is suitably methyl methacrylate or styrene.

The non-polymerizable components of the liquid carrier should be sufficiently volatile to be volatilized during the process of applying the composition to predetermined areas of the hot mold surface and prior to the introduction of the curable composition. is there. Therefore, the most suitable materials are those that can be volatilized from surfaces maintained in the range of 50-100 ° C. Suitable non-polymerizable materials include methyl ethyl ketone, toluene and xylene.

Regardless of the composition of the liquid carrier, it should also serve the function of dissolving the drying oil modified alkyd resin.

The preforming polymer of the coating is a polymer that is either compatible with the polymer that forms the body of the final molded article or is less incompatible with the matrix polymer, the presence of which results in a loss of physical properties in the surface area of the molded article. Should be Where the composition forming the matrix polymer of the molded article is a composition based on methyl methacrylate, a polymer or copolymer of methyl methacrylate, especially a relatively low molecular weight material having a number average molecular weight of less than 200,000, preferably less than 50,000. Is effectively used.

The preformed polymer component may be present as a material having surface active properties that are engineered to help disperse the solid particulate material present in the color contrast composition. Such polymeric dispersants are described in British Patent Specification 1493.
Fully described in 393. These dispersants are effective in providing a low viscosity composition of a dispersion station of at least 20% by volume of finely divided particulate filler material in a liquid polymerizable carrier and have a molecular weight of at least 500, preferably at least 2000. , At least one polymer that is solvated in a liquid polymerizable carrier, and one or more groups that are capable of being associated with particles of the filler material and providing a fixing cure with these particles. Including. Typical polymeric dispersants for effective dispersion of finely divided materials in methylmethacrylate monomers include, for example, carboxylic acid, epoxy, hydroxyl and amino groups provided by copolymerization of monomers with suitable functional groups. It is a polymer of methyl methacrylate having such a functional group. The concentration of the preformed polymer in the color contrast composition is preferably in the range of 0.1 to 20% by weight of the composition, with the concentration of the drying oil-modified alkyd in order to give a molded article having a sufficiently hard surface. It should be at least half, preferably at least equivalent to this concentration.

According to the present invention, there is also provided a composition suitable for use in the method of the present invention. The composition comprises: (a) a liquid carrier comprising a mixture of 0 to 100 parts by weight of a polymerizable liquid and a corresponding 100 to 0 parts by weight of a non-polymerizable volatile organic solvent; (b) 0.1 of the total composition. To 10% by weight of an inorganic pigment-like colorant or 0.0001 to 1% by weight of an organic pigment or dye, (c) 0-60% by weight of the synthetic composition, a finely divided filler having an average particle size of less than 5 microns. (D) 0.1-50% by weight, soluble in a liquid carrier,
A dry oil-modified alkyd resin, and (e) a preform polymer soluble in a liquid carrier, present in a concentration of at least half the concentration of the dry oil-modified alkyd resin, comprising components (a), (b), (c) , (D) and (e) total 100% and (a) is present at a concentration of at least 25% by weight of the total composition.

The composition of the present invention, when applied to a predetermined area of the mold surface, is deposited as is on the mold surface within the predetermined area during subsequent loading of the curable composition into the mold. Not only provides a composition that gives an attractive, transferred to a predetermined portion of the surface of the molded article during the molding process.
It will be integrated into the molding to give a durable surface. This composition also has the advantage that it can be easily sprayed with available spray equipment, if it has a suitable viscosity, and can easily be redispersed in the sprayable composition after a given storage period. give.

The method of the present invention corresponds to a predetermined area of the surface of a molded article as a result of a curing operation after the composition that gives the color contrast with respect to the color of the body of the article to be molded moves to the surface of the molded article. It is carried out by applying a composition of a color having a desired contrast onto a predetermined area of the mold surface in the portion to be treated. The preferred method of application to the mold surface is by spraying. During this mold coating operation and the subsequent mold filling operation, the mold part
Hold at elevated temperature. In order to optimize the conditions for moving the composition from the mold surface so as to be integrated with the molded product, it is effective to polymerize the curable material to be introduced as the body material of the molded product. It is preferred that a free radical initiator be present in the composition applied to the mold surface. Given the relatively short life of one part of the free radical initiator, it is preferably added to the composition just prior to application to the mold. The free radical initiator used should be such that it is an effective initiator at the temperatures used in the curing operation and is the same catalyst used to cure the body material in the mold.

The concentration of free radical initiator will depend on the nature of the initiator. Typical initiator concentrations range from 0.001 to
It is 3.0% by weight.

After the contrast-defining composition has been applied to the mold surface, the corresponding portions of the mold are brought together to provide a cavity that defines the desired product shape. The appropriate curable composition is introduced into the mold and held at elevated temperature until it is sufficiently cured to be removed from the mold. Although the composition of the present invention provides a composition that can be used under conditions of broader tolerance than those described in EP 61245, the introduction of the curable composition into a prepared mold provides It should be noted that the conditions should be such that there is no direct collision of the composition entering the mold surface prepared with the color contrast composition of the present invention. A particular advantage of the composition of the present invention is that it can be hardened after being applied to the desired predetermined area of the heated mold surface, immediately after being prepared, without waiting for the time for the coating to harden. That is, it can be filled with the composition.

In addition to providing improved coating compositions over the compositions described in European Patent Publication 61245, the compositions of the present invention undergo a molding process that will impart improved properties to the finished articles. Give you the improvement that you can. These process improvements result from the need to use previously used color contrast compositions at high molding temperatures to properly transfer the contrast composition into the molded article. In the case of a highly filled curable composition based on methyl methacrylate, the surface of the mold on which the outer surface of the product is molded is on the order of 85 ° C during the filling operation, and as soon as possible after the mold is filled. The condition that the temperature should be raised to 100 ° C is required for proper operation. The temperature of the other mold surface should initially be lower than the temperature at which the outer surface is formed, but in the final stage of curing it should be raised to the same temperature.
The use of the composition of the present invention provides very low mold temperatures,
It has been shown that satisfactory results are obtained at temperatures at least 5 ° C lower. Nevertheless, the mold temperature should be at a temperature at which polymerization of the polymerizable material involved can be initiated, and at which volatile solvent, if present, can be removed. The mold surface to which the coloring composition is applied is preferably at a temperature of at least 50 ° C.
The advantage of this method is that it gives a molded article with a low residual molding stress and an improvement in the physical properties that depend on the molecular weight of the matrix polymer.

The invention will be further described according to the following examples.

Example 1 A sprayable composition was prepared by mixing the following ingredients. 1st stage parts by weight Methyl methacrylate containing 0.01% by weight of polymerization initiator 47 Glycol dimethacrylate 1.1 Finely pulverized silica (average particle size 2 micron) 41 Polymer dispersant (98: 2 Methyl methacrylate / methacrylic acid copolymer, Mw110000 (GPC)) 0.7 γ-methacryloxypropyltrimethoxysilane 0.1 97: 3 methylmethacrylate: ethyl acrylate copolymer, number average molecular weight 40000 4.8 Dry oil modified alkyd resin, as a 50% by weight solution in white spirit (under symbol X102-744) (Available from ICI) 4.8 Stage 2 parts by weight methyl methacrylate 44 Same polymer dispersant as in stage 1 6 Iron oxide 50 100 parts by weight of stage 1 composition mixed with 6 parts by weight of stage 2 composition Immediately before use, 100 parts by weight of this mixture are added to 50 parts by weight of slow thinner (available from Imperial Chemical Industries 2K-P850-1276) and 1 part by weight of the free radical initiator bis- (4-t-butylcyclohexyl) peroxydicarbonate was dissolved in this mixture. This composition was tested using a kitchen sink mold. The composition was sprayed onto a predetermined area of the mold surface (corresponding to the sink rim and drainage area of the sink) where the outer surface of the sink was to be polymerized. Mold surface
Hold at 80 ° C. Next, the mold is closed and the supporting mold surface is set to 50.
Hold at ℃. 73% by weight of filler (UK patent specification 1493
A curable composition containing (prepared according to Example 5 of 393) was poured into a closed mold. Raise the temperature of the mold surface little by little
After 10 minutes, the temperature of both mold parts was set to 85 ° C. The mold temperature was raised little by little over the next 10 minutes so that both mold parts reached 100 ° C. The composition was substantially fully polymerized at this time, but the cycle was completed using a post cure time of 10 minutes at 100 ° C. The cured product removed from the mold has an attractive color contrast effect, and the coating composition sprayed onto the mold has a controlled surface of the sink without the flow of sprayed coating. Had been moved to.

The composition consisting of the mixture of the first-stage composition and the second-stage composition was perfectly suitable for mixing and sale, since the pigment and the filler were dispersed for a considerable period of time.
The mixture could be easily redispersed even after solids had settled after long-term storage. Upon addition of the thinner and free radical catalyst, the mixture was stable and ready for spraying for a time sufficient for use of the dispersion.

Example 2 The procedure of Example 1 was repeated except that no free radical catalyst was used. Although similar full contrast color areas were obtained on the sink, there was some evidence of cracking under the conditions used in Example 1. Although the use of higher initial polymerization temperatures eliminates this problem, this example illustrates the benefits of compositions containing free radical catalysts.

Example 3 The procedure of Example 1 was repeated except no slow thinner was used. Although the composition was easy to atomize, a larger droplet size spray was obtained, which also showed the disadvantage of producing more dust than the composition of Example 1. The transition from the contrast region to the base color region in the final product was less attractive.

Comparative Example A In this example, the composition of Example 1 was prepared except for the drying oil modified alkyd resin. Although the composition was well atomized,
After repeating the polymerisation operation of Example 1, the applied contrast coating was washed away by coating disturbances during the subsequent polymerisation filling operation of the body of curable composition.

Comparative Example B In this example, an alkyd resin was dissolved in another film forming resin, xylene, an acrylic copolymer (IC
(Available as X190-294 from Company I). The resulting sink was inadequate due to surface imperfections when produced by the polymerization operation.

Comparative Example C A composition was prepared according to Example 1 except that the second stage pigment dispersion consisted of 50 parts pigment, 5 parts polymeric dispersant and 45 parts dibutyl phthalate (instead of methyl methacrylate). . Dibutyl phthalate has a low volatility at 80 ° C. The resulting sinks exhibited a very noticeable wash-off defect in coaching. The same performance was experienced with a polymerization temperature of 100 ° C.

Comparative Example D In this example, the alkyd resin of Example 1 was replaced with a urethane modified alkyd resin designated X101-373 available from ICI. The resulting sink was clearly inferior in appearance to that of Example 1.

Example 4 The composition of Example 1 was prepared except that the concentration of alkyd resin in Example 1 was reduced to 0.5 parts by weight. The appearance of the obtained sink was almost the same as that of Example 1 and was good.

Example 5 The general procedure of Example 1 was repeated using various drying oil modified alkyd resins, omitting finely divided silica from the first stage composition. The composition used in this test was as follows. First-stage parts by weight Methyl methacrylate 40 Modified alkyd resin (listed below) 10 Methyl methacrylate 97: 3 30% solution of methyl methacrylate: ethyl acrylate copolymer in Example 30 30 Second-stage composition as in Example 1 Slow thinner 2K-P850-12 76) 20 1 part of bis- (4-t-butylcyclohexyl) peroxydicarbonate was dissolved in the mixture before carrying out the procedure of Example 1 to produce moldings.

The modified alkyl resins evaluated were as follows:

A.X102-714 Long oil length dry oil alkyd based on linseed oil / pentaerythritol / phthalic anhydride with 67% oil length and 62% solids by weight in white spirit.

B.X101-479 52% Oil Length and 3: 1 White Spirit:
Medium oil length drying oil alkyd based on complex sunflower oil having a solids content of 56% by weight in a xylol mixture.

C.X103-686 Short oil length semi-dry oil alkyd based on dehydrated castor oil / glycerol / phthalic anhydride with 43% oil length and 50% solids by weight in xylol.

These materials are commercially available from Imperial Chemical Industries.

The performance of these compositions was good and, although indistinguishable from each other, was slightly inferior to that of the composition of Example 1.

Example 6 In this example, the general procedure of Example 1 was repeated except that no finely divided silica was used. The components of this composition were as follows:

Methyl methacrylate 58 parts by weight Alkyd resin from example 1 (X102-744) 10 parts by weight Same as used in example 1 97: 3 methyl methacrylate: ethyl acrylate copolymer (as a 30% by weight solution in methyl methacrylate) 20 parts by weight Pigment composition (second stage composition of Example 1) 12 parts by weight A mixture of these components was diluted with the slow thinner (20 parts) used in Example 1. 1 part free radical initiator bis-
(4-t-Butylcyclohexyl) peroxydicarbonate was dissolved in the mixture and used to make a kitchen sink under the conditions described in Example 1. A sink was produced that had an excellent appearance at least as good as that of Example 1.

Example 7 The procedure of Example 1 was repeated using the following mixture to mold a kitchen sink to provide color contrast on the sink rim and drainage pad area.

Methyl methacrylate 30 parts by weight Pigment dispersion (second stage dispersion of Example 1) 2 parts by weight X102-744 alkyd resin 10 parts by weight Polymer dispersant (same as used in Example 1), 25% by weight solution in methyl methacrylate 40 parts by weight Slow thinner (same as in Example 1) 20 parts by weight Performance slightly worse than in Example 6 was obtained with this composition.

Claims (9)

[Claims] 1. A method of curing a curable composition between corresponding mold parts to produce a formed article having a color contrast region on the surface of a product, while maintaining the mold part at an elevated temperature, A method comprising applying a coloring composition to at least one predetermined area of a mold part, closing the mold part to form a mold cavity, and curing the composition in the cavity, the coloring composition comprising: A) a liquid carrier comprising a mixture of (a) 0-100 parts by weight of a polymerizable liquid and a corresponding 100-0 parts by weight of a non-polymerizable volatile organic solvent, (b) 0.1-10% by weight of the total composition An inorganic pigment-like colorant or 0.0001 to 1% by weight of an organic pigment or dye, (c) 0-60% by weight of the total composition, a finely divided filler having an average particle size of less than 5 microns, (d) 0.1-50% by weight, soluble in a liquid carrier,
A dry oil-modified alkyd resin, and (e) a preform polymer soluble in a liquid carrier, present in a concentration of at least half the concentration of the dry oil-modified alkyd resin, comprising components (a), (b), (c) , (D) and (e) total 100% and (a) is present in a concentration of at least 25% by weight of the total composition. 2. The coloring composition applied to a predetermined area of the mold comprises a free radical-generating initiator for the curable composition to be introduced into the mold. The method described. 3. The liquid carrier of the coloring composition comprises at least 5 parts of polymerizable liquid per 100 parts of liquid carrier,
A process according to claim 1 or 2, wherein the polymerizable liquid is copolymerizable with the curable material of the curable composition to be introduced into the mold and has a boiling point below 150 ° C. 4. A method according to any of claims 1 to 3, wherein the curable composition is based on methyl methacrylate. 5. A method according to claim 4, wherein the coloring composition comprises at least 5 parts per 100 parts of liquid carrier of a polymerizable liquid copolymerizable with methyl methacrylate. 6. The mold surface to which the coloring composition is applied is 85 ° C.
A method as claimed in claim 4 or 5, which is below the temperature of at least 50 ° C. 7. A coloring composition for use in the production of a molded article having a color contrast area on the surface of a product, which comprises (a) 100 to 0 parts by weight corresponding to 0 to 100 parts by weight of a polymerizable liquid. A liquid carrier comprising a mixture with a non-polymerizable volatile organic solvent of (b) 0.1 to 10% by weight of the total composition of an inorganic pigmented colorant or 0.0001 to 1% by weight of an organic pigment or dye, (c) ) 0-60% by weight of the total composition, a finely divided filler having a mean particle size of less than 5 microns, (d) 0.1-50% by weight, soluble in a liquid carrier,
A dry oil-modified alkyd resin, and (e) a preform polymer soluble in a liquid carrier, present in a concentration of at least half the concentration of the dry oil-modified alkyd resin, comprising components (a), (b), (c) , (D) and (e) total 100% and (a) is present in a concentration of at least 25% by weight of the total composition. 8. The liquid carrier comprises a polymerizable liquid having a boiling point of less than 150 ° C., which is at least 5 parts per 100 parts of liquid carrier and is copolymerizable with the curable material to be introduced into the mold. The coloring composition according to claim 7. 9. A coloring composition according to claim 7 or 8, wherein the composition comprises 0.1 to 20% by weight of a preform polymer soluble in a liquid carrier and having a number average molecular weight of less than 200,000. .