JPH0780870A - Manufacture of in-mold covering molded article - Google Patents

Abstract

PURPOSE:To obtain a covered molded article, in the covering layer of which color uniformity is present and in which the adhesion of the covering layer to the base material of the molded article is excellent, in the manufacturing of an in-mold covering molded article, in which the covering layer is formed by pouring covering material, which contains at least two different colored pigments. CONSTITUTION:After the pouring of covering material in a mold, the pressure intensifying process is started during the period ranging from the point of time T1, at which the exothermic expansion peak of the covering material is detected, to T2, 20sec after the detection of the peak.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of an in-mold coated molded article in which a coating material containing at least two kinds of coloring pigments is injected into a mold to form a coating layer when molding a thermosetting molding material. The present invention relates to a method, and more particularly to a method capable of producing a coated molded article which is free from color unevenness of a coating layer and has excellent adhesion to a molded article substrate.

[0002]

2. Description of the Related Art Conventionally, as a molded product molded by using a thermosetting molding material, a molded product made of SMC (sheet molding compound) or BMC (bulk molding compound) is well known. Further, an in-mold coating molding method is known in which a coating layer is formed in a mold when a molded product made of these thermosetting molding materials is obtained.

Preferable molding pressurizing conditions in the in-mold coating molding method include magazine "Plastics", Vol. 41, No. 5
No. 96, page 102 to page 102, "In-Mold Coating Molding Method".

In the molding pressurizing condition shown in FIG. 2, first, the pressure is
P₁(60-100kg / cm²) By thermosetting
Fill the material into the mold. Next, prevent sink marks and flatten the molded product.
Apply pressure P to improve lubricity₂(20-50kg / c
m²). And the thermosetting molding material is half
When in the curing stage, apply pressure P₃(0-40kg / c
m ²) And the coating material is injected. Complete injection of coating material
After finishing the pressure P_Four(40-80kg / cm²Up to)
The desired surface of the molded article substrate
Fill so as to reach the surface part. After filling the coating material,
Pressure P_Five(20-60kg / cm²) Depressurize to
The coating material is cured to obtain a molded article with a coating layer.

Conventionally, the pressure increase after the injection of the coating material is generally performed instantaneously after the injection.

[0006]

However, in the conventional in-mold coating molding method as described above, when a coating material containing two or more kinds of coloring pigments of different colors is used, color unevenness occurs in the coating layer. There was a problem. Further, in some cases, there is a problem that a molded product having poor adhesion to the molded product substrate is produced.

The object of the present invention is to solve the above-mentioned conventional problems, and when forming a coating layer by injecting a coating material containing at least two kinds of coloring pigments, there is no uneven color of the coating layer, Another object of the present invention is to provide a method capable of producing a coated molded article having excellent adhesion to a molded article substrate.

[0008]

Means for Solving the Problems The production method of the present invention is such that, when a thermosetting molding material is heated / pressurized in a mold, when a molded article substrate made of the molding material is in a semi-curing stage,
A step of injecting a coating material containing at least two kinds of color pigments into a mold and then increasing the pressure in the mold, the pressure increasing step is performed from the time when the exothermic expansion peak of the coating material is detected to 20 seconds after the peak detection. It is characterized by starting in between.

FIG. 1 shows the steps in the manufacturing method according to the present invention.
In the figure which shows the press pattern which shows the time change of form pressure
is there. As shown in Figure 1, first fill the mold with the molding material.
Molding pressure P₆Can be applied. This molding pressure P
₆Is generally 20-150 kg / cm²It is a degree. next
After filling the mold with the molding material, the pressure is reduced. At this time
The rate of pressure change is not a particular issue, and this depressurization process is
The pressure may be reduced in several stages. Molding pressure P after depressurization₇
Is 0 to 40 kg / cm²Within the range of
More preferably 5 to 20 kg / cm²Within the range of
is there. Molding pressure P ₇Is 40 kg / cm²Greater than
The shear stress applied to the coating material increases, which causes
Different colored pigments contained in the covering material separate, resulting in
Color unevenness may occur in the coating layer.

The coating material is injected into the mold when the molded article substrate made of the thermosetting molding material is in a semi-cured state.
This is shown in FIG. 1 as paint injection. The time point at which the exothermic expansion peak of the injected coating material is detected by the pressure sensor provided in the mold is shown as T _{1 in} FIG. T ₂ is a time point 20 seconds after this T ₁ , and in the present invention, pressure increase in the mold is started between T ₁ and T ₂ . That is, in the present invention, T ₁ to 20 at the latest.
Increase the pressure in the mold within seconds. In the present invention, more preferably, the pressure is increased within 10 seconds from T ₁ .

When pressure increase is started earlier than T ₁ ,
A large shear stress is generated in the coating material that can be in a fluid state, and the different color pigments contained in the coating material are separated, resulting in uneven color in the coating layer. Further, when the pressure increase is started at a time later than T ₂ , compressive stress is generated in the completely cured coating material, and the adhesion of the coating layer to the base material deteriorates.

The forming pressure P ₈ after the pressure increase is 50 to 150 k.
It is preferably in the range of g / cm ² , and more preferably in the range of 60 to 125 kg / cm ² . Fifty
If the molding pressure is lower than kg / cm ^2, the adhesion of the coating material may be deteriorated, and if the molding pressure is higher than 150 kg / cm ² , color unevenness may occur.

After increasing the molding pressure P ₈ , a pressure reducing step may be provided to cure the coating material. In the present invention, when the molded article substrate made of the thermosetting molding material is in a semi-cured state, the thermosetting molding material resin is filled in the mold, and even when the coating material is injected, the coating material is It shows the state that the minimum curing condition is reached without entering the thermosetting molding material or disturbing the surface.

In the present invention, it is necessary to measure the exothermic expansion peak of the coating material injected into the mold, but such exothermic expansion peak can be measured by providing a pressure sensor in the mold. The pressure sensor is preferably provided on the horizontal part of the mold, and may be provided on either side of the coating material side or the molded article substrate side.

As the thermosetting resin used as the coating material in the present invention, a reactive in the molecule capable of forming a three-dimensional network structure by cleavage addition reaction of a double bond using a thermally decomposable radical catalyst. An unsaturated polyester resin having a double bond, an epoxy acrylate (vinyl ester) resin, a urethane acrylate resin or the like is used. These resins may be used alone or as a mixture of plural kinds.

Further, as the low shrinkage agent for the above coating material,
Thermoplastic resins such as polyvinyl acetate, polymethyl (meth) acrylate, polyethylene, ethylene vinyl acetate copolymer, vinyl acetate-styrene copolymer, polybutadiene, saturated polyesters, saturated polyethers, etc. -10 parts by weight can be used.

If necessary, the coating material may include styrene, alphamethylstyrene, divinylbenzene,
Copolymerizable monomers such as vinyltoluene, diallyl phthalate, various acrylate monomers, and various methacrylate monomers are used with respect to 100 parts by weight of the resin component (the total amount of the thermosetting resin and the low-shrinking agent resin added if necessary). 5 to 40 parts by weight can be added.

As the color pigment contained in the coating material used in the present invention, conventionally known pigments are used. For example, titanium oxide, benzine yellow, anthraquinone yellow,
Titanium yellow, Hansa yellow, molybdate orange, yellow lead, disazo yellow, benzine orange, quinacridone red, chrome green, phthalocyanine green, miloli blue, cobalt blue, phthalocyanine blue, iron oxide (Bengala), Various well-known and commonly used ones such as carbon black and iron black are used.

The preferable amount of the color pigment is 3 to 200 parts by weight based on 100 parts by weight of the resin component (the total amount of the thermosetting resin, the copolymerizable monomer, and the low-shrinking agent resin added if necessary). If it is less, the hiding power is insufficient, and if it is more, the viscosity becomes higher and the flow in the mold becomes worse.

In the above coating material, an appropriate amount of extender pigment, that is, an elemental mineral such as diamond; a halogenated mineral such as rock salt and potassium rock salt; a carbonate mineral such as calcium carbonate; Phosphate minerals such as; carna-stones and other vanadate minerals; barite (barium sulfate), gypsum (calcium sulfate) and other sulfate minerals; borax and other borate minerals; perovskite and other titanium Silicate minerals such as mica, talc, pyrophyllite, kaolin, quartz and feldspar; Metal (hydr) oxides such as corundum (aluminum oxide) and aluminum hydroxide;
Natural or artificial minerals such as glass products such as (hollow) glass spheres, processed or refined or processed minerals thereof, and mixtures thereof are used.

The amount of the filler added is preferably 0 to 200 parts by weight as the sum of the color pigment and the extender pigment with respect to 100 parts by weight of the thermosetting resin. If the amount added exceeds 200 parts, it will be difficult to uniformly disperse the color pigments and extender pigments in the resin and the monomer, and the viscosity will become too high, resulting in poor fluidity in the mold and the entire surface. It becomes difficult to spread.

Further, if necessary, the above coating material may include ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, alkyl peresters, percarbonates, peroxyketals and the like. Known initiators; dimethylaniline, cobalt naphthenate, and other known curing accelerators; parabenzoquinone and other polymerization inhibitors; carbon black, titanium oxide, iron oxide, cyanine pigments, aluminum flakes, nickel powder, gold powder, silver powder Pigments such as: Azo dyes, anthraquinone dyes, indigoid dyes, stilbene dyes, etc .; Conductivity-imparting agents such as carbon black; Emulsifiers; Metal soaps such as zinc stearate; Aliphatic phosphates, lecithin release agents A suitable amount of agents can be added depending on the application and purpose

The thermosetting resin composition used as the thermosetting molding material in the present invention may be appropriately blended with various materials as in the coating material composition. That is, unsaturated polyester resin, vinyl ester resin, urethane acrylate resin, etc. are used as the thermosetting resin, and various copolymerizable monomers, low-shrinking agents, various fillers, colorants, initiators, reinforcing agents are used as necessary. Materials, additives, etc. can be added.

As a particularly general-purpose example of such a molding material, for example, an unsaturated polyester resin is dissolved in styrene, a low-shrinking agent made of a thermoplastic resin is added, and an organic peroxide as an initiator is used. It has been conventionally used that SMC or BMC is formed by adding various kinds of fillers and reinforcing materials such as glass fiber.

[0025]

In the production of an in-mold coated molded article in which a coating material containing at least two kinds of color pigments is injected to coat the surface of the molded article, the present inventors cause color unevenness of the coating layer or decrease in adhesion. As a result of various studies on the cause, it was found that the timing of pressure increase in the mold after injection was related. That is, it was found that when the pressure was increased earlier than the exothermic expansion peak of the coating material, shear stress was generated in the color pigment contained in the coating material in the uncured state, resulting in color unevenness. 20 from the exothermic expansion peak of the coating material
It was found that when the pressure was increased at the time of exceeding seconds, compressive stress was applied to the completely cured coating layer, the interface strength between the base material and the coating layer was reduced, and the adhesion with the base material was reduced. In the present invention, by increasing the pressure within 20 seconds at the latest from the time when the exothermic expansion peak of the coating material is detected, a coating layer having no color unevenness and excellent adhesion is formed.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be clarified by giving non-limiting examples and comparative examples of the present invention. In the following, “part” means part by weight unless otherwise specified.

Preparation of SMC After mixing the materials having the following compositions and thoroughly stirring, SM
By C impregnation device, glass fiber (made by Asahi Fiber Glass, roving, trade name: ER4630LBD166W
(Cut into a length of 25 mm) 60 parts are impregnated with S
I got MC. The obtained SMC was aged at 40 ° C. for 24 hours.

1. 70 parts of unsaturated polyester resin solution (about 60% by weight of isophthalic acid-based unsaturated polyester resin dissolved in about 40% by weight of styrene monomer) Polystyrene low-shrinking agent resin (about 30% by weight of polystyrene resin dissolved in about 70% by weight of styrene monomer) 30 parts 3. 120 parts of calcium carbonate powder (NS-100: Nitto Koka Co., Ltd.) 4. 4. Hardening agent (tertiary butyl peroxo 2-ethylhexanoate content 97 wt%) 1 part 5. Thickener (magnesium oxide powder, Kyowamag 15)
0: made by Kyowa Chemical Industry Co., Ltd.) 1. Internal mold release agent (zinc stearate: Sakai Chemical Industry Co., Ltd.)
Preparation of 3 parts coating material A Epoxy acrylate resin liquid (lipoxy R802,
Showa High Polymer Co., Ltd.) 100 parts 2. Extender pigment: Calcium carbonate (NS-100: manufactured by Nitto Koka Co., Ltd., average particle size: about 2 μm) 50 parts 3. Hardener (tertiary butyl peroxobenzoate content 98 wt%) 1 part 4. 4. White pigment (titanium oxide, SR-1, manufactured by Sakai Chemical Industry Co., Ltd., average particle size: about 0.24 μm) 40 parts 5. Red pigment (Dipyroxide color # 9700, manufactured by Dainippon Kasei Kogyo Co., Ltd., average particle size 0.1 μm) 10 parts The above materials were mixed and sufficiently stirred and kneaded to obtain a pink coating material A. .

Preparation of coating material B 1. Polyurethane glycol (made by Wako Pure Chemical Industries, Ltd., average molecular weight: about 1000), tolylene diisocyanate (made by Wako Pure Chemical Industries, Ltd.) and 2-hydroxyethyl methacrylate (made by Wako Pure Chemical Industries, Ltd.) in a known and commonly used method, urethane acrylate A resin was synthesized and dissolved in styrene to prepare a urethane acrylate resin liquid (average molecular weight: 1600, styrene concentration in resin liquid: about 40%).

100 parts of the urethane acrylate resin 2. Extender pigment: Calcium carbonate (NS-100) 50 parts 3. Hardener (tertiary butyl peroxobenzoate content 98 wt%) 1 part 4. White pigment (titanium oxide, TYPURE 900, manufactured by DuPont) 90 parts 5. Yellow pigment (titanium yellow, yellow 9121, manufactured by Dainippon Kasei Kogyo Co., Ltd.) 10 parts The above materials were mixed, sufficiently stirred and kneaded to obtain a cream-color coating material B.

Molding Conditions The deep-drawing molded products shown in FIGS. 3 and 4 were molded under the molding conditions described below. The dimensions of the molded product are length × width × height = about 600 mm × about 350 mm × about 250 mm, and the projected area of the mold is about 2000 cm ² . Also,
The thickness of the molded product is about 5 mm. Further, the angles of the inclined surfaces A to D of the molded product are A: 85 degrees, B: 85 degrees,
C: 87.5 degrees and D: 75 degrees.

As the mold, a mold having a high-pressure injection machine manufactured by Morel Co. attached to the center of the upper mold and a pressure sensor (made by Kistler Co.) attached at a position 5 cm away from the injection machine was prepared. Set on a 300 ton press machine manufactured by the company,
Molding was performed by setting the upper mold and the lower mold at a predetermined temperature described below.

Example 1 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C.

SMC (3.4 kg) was charged and pressure molding was performed for 10 seconds at a pressing pressure of 125 kg / cm ² . Pressing pressure was instantaneously reduced to 2.5 kg / cm ² and 4
Hold for 0 seconds.

Then, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel). After the injection, the press pressure is 2.5 kg / cm ² for 35 seconds, and the pressure is instantaneously increased to 125 kg / cm ² (after 5 seconds of exothermic expansion peak), and the press and heat are applied for 65 seconds. By holding the pressure, a molded article coated with the coating material was obtained.

The exothermic expansion peak of the coating material was 80 seconds. The coating layer of the obtained molded product had no color unevenness and was excellent in adhesion.

Example 2 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The pressing pressure is momentarily set to 2.5 kg / cm ²
The pressure was reduced to and held for 40 seconds. Then, 100 ml of the coating material A was injected from the center of the upper mold by an injector (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 50 seconds, press pressure is instantaneously 70
Increased pressure to kg / cm ² (after 10 seconds of exothermic expansion peak), 6
Pressing and heating for 0 seconds and maintaining the pressing pressure, a molded article coated with the coating material was obtained.

The exothermic expansion peak of the coating material was 90 seconds. The coating layer of the obtained molded product had no color unevenness and was excellent in adhesion.

Example 3 The press pattern is shown in FIG. The upper mold was heated to 135 ° C and the lower mold was heated to 120 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

Pressing pressure is instantaneously set to 2.5 kg / cm ²
The pressure was reduced to and held for 90 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 70 seconds to increase the press pressure to 70
Increased pressure to kg / cm ² (after 10 seconds of exothermic expansion peak), 1
Pressing and heating were carried out for 30 seconds and the pressing pressure was maintained to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 160 seconds. The coating layer of the obtained molded product had no color unevenness and was excellent in adhesion.

Example 4 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The pressing pressure was instantaneously reduced to 15 kg / cm ² and maintained for 40 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After the injection, with a pressing pressure of 15 kg / cm ² ,
It is heated and pressurized for 35 seconds, and the press pressure is instantaneously 125 kg.
The pressure was increased to / cm ² (after an exothermic expansion peak of 5 seconds), followed by pressurizing and heating for 65 seconds to maintain the press pressure, to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 80 seconds. The coating layer of the obtained molded product had no color unevenness and was excellent in adhesion.

Comparative Example 1 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The press pressure is instantaneously increased to 2.5 kg / cm ²
The pressure was reduced to and held for 40 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , press for 15 seconds and press the pressure to 12 momentarily.
Increase the pressure to 5 kg / cm ² (15 seconds before the exothermic expansion peak),
Pressurization and heating were performed for 85 seconds and the press pressure was maintained to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 80 seconds. Color unevenness was generated on the surface B of the obtained molded product.

Comparative Example 2 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

Pressing pressure is instantaneously set to 2.5 kg / cm ²
The pressure was reduced to and held for 40 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 70 seconds, press pressure is instantly 12
Increase the pressure to 5 kg / cm ² (after 40 seconds of exothermic expansion peak),
Pressing and heating were carried out for 30 seconds and the pressing pressure was maintained to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 80 seconds. The adhesiveness of the obtained molded product D surface was 23/100.

Comparative Example 3 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The pressing pressure is instantaneously set to 2.5 kg / cm ²
The pressure was reduced to and held for 40 seconds. Then, 100 ml of the coating material A was injected from the center of the upper mold by an injector (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 20 seconds, press pressure momentarily 70
Increased pressure to kg / cm ² (20 seconds before exothermic expansion peak), 9
Pressing and heating for 0 seconds and maintaining the pressing pressure, a molded article coated with the coating material was obtained.

The exothermic expansion peak of the coating material was 90 seconds. Color unevenness was generated on the surface B of the obtained molded product.

COMPARATIVE EXAMPLE 4 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

Pressing pressure is instantaneously set to 2.5 kg / cm ²
The pressure was reduced to and held for 40 seconds. Then, 100 ml of the coating material A was injected from the center of the upper mold by an injector (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 70 seconds to increase the press pressure to 70
Increased pressure to kg / cm ² (after 30 seconds of exothermic expansion peak), 4
Pressing and heating for 0 seconds and maintaining the pressing pressure, a molded article coated with the coating material was obtained.

The exothermic expansion peak of the coating material was 90 seconds. The adhesiveness of the D surface of the obtained molded product was 40/100.

Comparative Example 5 The press pattern is shown in FIG. The upper mold was heated to 135 ° C and the lower mold was heated to 120 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The press pressure is instantaneously increased to 2.5 kg / cm ²
The pressure was reduced to and held for 90 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 20 seconds, press pressure momentarily 70
Increased pressure to kg / cm ² (40 seconds before exothermic expansion peak), 1
Pressurization / heating was performed for 80 seconds and the press pressure was maintained to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 160 seconds. Color unevenness occurred on the B and D surfaces of the obtained molded product.

Comparative Example 6 The press pattern is shown in FIG. The upper mold was heated to 135 ° C and the lower mold was heated to 120 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The press pressure is instantaneously increased to 2.5 kg / cm ²
The pressure was reduced to and held for 90 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After injection, press pressure 2.5 kg / cm
^{At 2} , heat and press for 100 seconds, press pressure momentarily 7
Increase the pressure to 0 kg / cm ² (after 40 seconds of exothermic expansion peak),
Pressing and heating were carried out for 100 seconds and the pressing pressure was maintained to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 160 seconds. The adhesiveness of the D surface of the obtained molded product was 3/100.

Comparative Example 7 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The pressing pressure was instantaneously reduced to 15 kg / cm ² and kept for 40 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After the injection, the pressing pressure is instantaneously 70 kg /
The pressure was increased to cm ² (30 seconds before the peak of exothermic expansion), and the mixture was pressed and heated for 100 seconds and the press pressure was maintained to obtain a molded article coated with the coating material.

The exothermic expansion peak of the coating material was 80 seconds. Color unevenness occurred on the entire surfaces of the obtained molded products A, B, C and D.

COMPARATIVE EXAMPLE 8 The press pattern is shown in FIG. The upper mold was heated to 150 ° C and the lower mold was heated to 135 ° C. Charge SMC 3.4kg, press pressure 125kg
It was pressure-molded at a pressure of / cm ² for 10 seconds.

The pressing pressure was instantaneously reduced to 15 kg / cm ² and maintained for 40 seconds. After that, 100 ml of the coating material B was injected from the center of the upper mold by an injection machine (manufactured by Morel).

After the injection, the press pressure was 15 kg / cm ² ,
Heat and press for 80 seconds, press pressure momentarily 125kg
The pressure was increased to / cm ² (after 50 seconds of exothermic expansion peak), 20 seconds of pressurization and heating to maintain the press pressure, and a molded article coated with the coating material was obtained.

The exothermic expansion peak of the coating material was 80 seconds. The adhesiveness of the D surface of the obtained molded product was 0/100. The results of Examples 1 to 4 and Comparative Examples 1 to 8 are summarized in Tables 1 and 2.

[0081]

[Table 1]

[0082]

[Table 2]

As is clear from the above results, by increasing the pressure within 20 seconds after detection of the exothermic expansion peak according to the present invention, it is possible to produce an in-mold coated molded product having no color unevenness and excellent adhesion. .

[0084]

According to the manufacturing method of the present invention, after injecting the coating material into the mold, the pressure increasing step is started from the time when the exothermic expansion peak of the coating material is detected to 20 seconds after the peak detection. . As a result, it is possible to pressurize the coating material in a semi-cured state without generating shear stress in the coloring pigment in the coating material, and therefore, even if a coating material containing at least two types of color pigments is used, It is possible to provide an in-mold coated molded article having a coating layer that is excellent in appearance and has excellent adhesion without causing unevenness.

[Brief description of drawings]

FIG. 1 shows a press pattern according to the present invention.

FIG. 2 is a view showing a press pattern in a conventional in-mold coating molding method.

FIG. 3 is a perspective view showing a molded product that is molded in the example according to the present invention.

FIG. 4 is a plan view showing a molded product that is molded in the example according to the present invention.

FIG. 5 is a diagram showing a press pattern of Example 1 according to the present invention.

FIG. 6 is a diagram showing a press pattern of Example 2 according to the present invention.

FIG. 7 is a diagram showing a press pattern of Example 3 according to the present invention.

FIG. 8 is a diagram showing a press pattern of Example 4 according to the present invention.

9 is a diagram showing a press pattern of Comparative Example 1. FIG.

FIG. 10 is a diagram showing a press pattern of Comparative Example 2.

FIG. 11 is a diagram showing a press pattern of Comparative Example 3.

FIG. 12 is a diagram showing a press pattern of Comparative Example 4.

FIG. 13 is a diagram showing a press pattern of Comparative Example 5.

FIG. 14 is a diagram showing a press pattern of Comparative Example 6.

FIG. 15 is a diagram showing a press pattern of Comparative Example 7.

16 is a diagram showing a press pattern of Comparative Example 8. FIG.

[Explanation of symbols]

P ₆ ... molding material filling the molding pressure P ₇ ... coating material injection during molding pressure P ₈ ... coating material exothermic expansion peak detection time of the curing molding pressure T ₁ ... coating material T ₂ ... exothermic expansion peak detection after 20 of the coating material Second elapsed time

Claims (1)

[Claims] 1. A coating material containing at least two kinds of coloring pigments when a thermosetting molding material is heated / pressurized in a mold and a molded article substrate made of the molding material is in a semi-curing stage. Is a method for producing an in-mold coated molded article, which comprises a step of intensifying the pressure in the die, wherein the pressure increasing step is performed after peak detection from the time when the exothermic expansion peak of the coating material is detected. A method for producing an in-mold coated molded article, which is started within 20 seconds.