JPH0691690A - Production of synthetic resin molded product - Google Patents

Abstract

PURPOSE:To prevent the warpage of a molded product by a method wherein a thermoplastic resin sheet is attached to the cavity of a mold and a thermoplastic resin weldable to said sheet and having a molding shrinkage factor of a definite value or less in the direction parallel to the surface of the sheet is injected in the mold to mold a laminated product. CONSTITUTION:A thermoplastic resin sheet 1 is attached to a cavity side 3 and a core side 4 and a movable core 6 are advanced by mold clamping to hold the sheet 1 between a fixed core 5 and the movable core 6. Since the movable core 6 has cushioning properties, the printing ink at the part held between the cores 5,6 of the sheet 1 is not damaged. A molded product having a three-dimensional shape integrated by pressure freely moves against the expansion, shrinkage and elongation of the sheet to be suppressed in warpage or expansion. A thermoplastic resin A (2) weldable to the sheet 1 and having a molding shrinkage factor of 0.1% or less in the direction parallel to the surface of the sheet is injected on the rear of the sheet to form a laminated molded product. Therefore, the laminated molded product does not generate deformation such as warpage or expansion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a monolithic molded article having a planar shape or a three-dimensional shape by laminating a thermoplastic resin on a thermoplastic resin sheet by injection injection.
More specifically, on an illuminated nameplate (that is, the nameplate that allows light to pass through only the letters and marks, and the other parts are shielded, and the letters and marks appear to float even in the dark due to the internal light source) or a sheet such as an opaque nameplate. Further, the present invention relates to a manufacturing method in which a thermoplastic resin is injection-injected to laminate-form a flat or three-dimensionally integrally molded product having no warp at a warp or a press-cut portion.
The nameplate is widely used for various electric and electronic devices such as automobiles, audios, VTRs, etc., and recently, due to the individualization of the design, the demand for a three-dimensional product rather than a planar structure is increasing.

[0002]

2. Description of the Related Art In the case of an opaque name plate, printing and painting on a flat sheet is performed by silk, screen printing, etc.
Even in the case of an illuminated nameplate in which only letters and marks are light-transmissive, it can be easily done by multilayer printing or masking painting. On the other hand, in the case of a three-dimensional product, if it has a convex shape, it may be possible to be processed by tampo, pad printing, etc. even by a post-processing method, but such a processing method becomes difficult for a product having a complicated uneven surface.

After multilayer printing or coating, a method of burning off the coating film with a laser on the light transmitting portion, printing the design and the light shielding portion in advance,
A painting molding method and a molding transfer method, which are made by inserting a coated sheet into an injection-molded resin and making it into a three-dimensional structure on the edge of the meter part like a car instrument panel, and flatten the design part. In this case, the panel body is a three-dimensional injection-molded product, only the sheet is processed into an illuminating sheet by the above-mentioned construction method, and the illumination nameplate can be produced by a method such as assembling to the panel body. However, it has the drawback of poor workability.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and uses a thermoplastic resin or a thermoplastic resin composition having a small molding shrinkage ratio by an injection molding method to obtain a flat shape or a solid shape without warpage. It is to provide a method for manufacturing a laminated product having a shape.

[0005]

[Means for Solving the Problems] The inventors of the present invention form a two-dimensional or three-dimensional laminated product by further stacking a thermoplastic resin on a thermoplastic resin sheet such as an illuminated name plate or an opaque name plate by injection molding. At that time, by using a resin having a specific molding shrinkage rate as the thermoplastic resin for injection molding, it was found that warpage of the molded article can be prevented,
The present invention has been completed.

That is, according to the present invention, a thermoplastic resin (S) sheet cut into a predetermined shape is mounted in a mold cavity, and the thermoplastic resin (S) and the thermoplastic resin (A) which can be welded are When injection-injected onto the sheet in the cavity to laminate-mold a flat or three-dimensional integrally molded product, a molding shrinkage rate (4 inches with a thickness of 3.2 mm) of thermoplastic resin (A) in the direction parallel to the sheet surface is used. The molding shrinkage ratio when a molded product is obtained by using a disc mold,
A method for producing a synthetic resin molded product, characterized in that a resin or a resin composition having a ratio of ((dimension of mold-dimension of molded product) / (dimension of mold)) of 0.1% or less is used. It is an invention.

The present invention will be described below. The thickness of the sheet made of the thermoplastic resin (S) used in the present invention is not particularly limited, but preferably 0.1 mm to 2.0 m.
When a sheet or film having a thickness of m is used, the product appearance and illumination performance are particularly improved. The above-mentioned sheet may be a mat-like sheet having a glossy smooth surface, a matte fine uneven surface, or a transparent or opaque sheet. If necessary, the sheet or film may be preliminarily printed, painted or provided with characters or marks by hot stamping or decoration. The material of the sheet is not particularly limited as long as it is a thermoplastic resin, such as PC (polycarbonate), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PMMA (acrylic resin), MS (methacrylate styrene). The above-mentioned sheet or film is punched into a mold shape in advance, or continuously supplied and cut into a shape that can be continuously collected.

In order to stack the thermoplastic resin (A) on at least one surface of the sheet, the sheet is mounted in the mold cavity with the movable side core retracted, and the core side is set to a position corresponding to the core of the cavity. Then, the thermoplastic resin (A) that is welded to the thermoplastic resin (S) is injected onto the sheet surface in the cavity. What can be used as the thermoplastic resin (A) is a molded product that is welded to the thermoplastic resin (S) and is parallel to the sheet surface by using a molding shrinkage ratio (thickness 3.2 mm, 4 inch disk mold). The molding shrinkage ratio at the time of obtaining, a value obtained by the formula 100 × (mold size−molded product size) / (mold size), hereinafter referred to simply as mold shrinkage) is 0.1% or less. Any material can be selected and used as appropriate. If the molding shrinkage ratio exceeds 0.1%, the laminated molded products warp and deform such as blister.

When a PC sheet is used as the thermoplastic resin (A) sheet, PC, PC / polyester resin,
PC / ABS resins, PC / polyamide resins, other polycarbonate resins (PC alloys), and various organic / inorganic fillers added to these resins as necessary to give a molding shrinkage of 0.1%. Use the following. Similarly, for the sheet obtained by molding the other thermoplastic resin (S), one having a weldability with the sheet to be used is appropriately selected. As a filler for reducing the molding shrinkage, glass, carbon, metal, whiskers, silicon carbide, fibrous organic / inorganic substances such as boron, flakes,
Beads and powders can be appropriately used. The blending ratio of the filler is determined in consideration of reduction of molding shrinkage and improvement of mechanical strength, heat resistance, etc., but when PC is used as the thermoplastic resin (S), it is 20 to 50.
Polycarbonate resin compositions containing wt.% Glass fiber are preferred.

As the injection molding conditions, known conditions of the resin material used are applied. When the thermoplastic resin (A) is injected into the mold cavity from the cylinder, the thermoplastic resin (A) is fused with a part of the thermoplastic resin (S) in a molten state by heat and pressure to form a laminated integral molded product. When the thermoplastic resin (A) is injected on one side of the sheet, a cushioning core is attached to the mold to cover a part of the sheet attached in the cavity, and the thermoplastic resin (S It is also possible to form a portion in which (1) is not laminated.

Next, in order to facilitate understanding of the present invention, an example will be described with reference to the drawings. 1 to 3 are schematic diagrams showing a manufacturing process of a name plate in which a partially three-dimensionally shaped portion for laminating a printed sheet with a molding resin and a flat sheet single-piece portion not laminated with the molding resin are mixed. The numbers in the drawings indicate 1: a sheet made of thermoplastic resin (S), 2: thermoplastic resin (A), 3: cavity side, 4: core side, 5 fixed side core, 6: movable side core.

In FIG. 1, the seat 1 is mounted on the cavity side 3 with the core side 4 and the movable side core 6 retracted to the core side. In FIG. 2, in the process of closing the mold, the core side and the movable side core are advanced to sandwich the sheet between the fixed side core 5 and the movable side core 6. Since the movable core has a cushioning property, when printing ink or the like is applied to the sandwiched portion, the printing ink is prevented from being damaged. A spring mechanism for operating the core or cavity, a cylinder mechanism driven by air, water, or hydraulic oil, or a conduction motor mechanism can be used.

In the injection step of FIG. 3, the thermoplastic resin (A) is injected and injected to shape the sheet into a three-dimensional shape. At this time, the thermoplastic resin (A) is not laminated on the portion of the sheet sandwiched between the fixed core and the movable core. In this case as well, a three-dimensional molded product that is integrated by the heat and pressure of the injection resin can be obtained, but since the mold core has cushioning properties, the seat can move freely, and the seat for shaping the three-dimensional shape can be obtained. Swelling and expansion of the sheet, and swelling of the single sheet portion affected by shrinkage during cooling, warpage and swelling of the entire surface can also be suppressed. After injection and injection of the thermoplastic resin (A), a three-dimensional molded article is obtained by cooling and releasing. Although the manufacturing method and the mold structure of the present invention have been described above, the present invention is not limited to the drawings as described above.

By utilizing the mold opening / closing operation during the injection molding process, the seat is sandwiched between the movable cores having cushioning properties, the seat is initially shaped by moving the core side, and then the molding material is injected. There is a multi-step shaping method in which the above product is obtained by additionally shaping up to the final shape other than the portion sandwiched by the core. The shape of the single sheet part is a hole shape product or non-target,
Even curved shapes can be accommodated. The range of the partial shaping ratio of the sheet is preferably within the proportional elastic deformation region of the sheet in terms of shape and within the yield elongation deformation region. As molding processing conditions, as the temperature of the molding material,
Molding is performed within a known temperature range of the selected molding material, and the mold temperature is preferably not higher than the heat resistant temperature of the ink when a printed sheet is used. According to the present invention, it is possible to increase the degree of freedom of design, and it is expected that the cost reduction and mass production of products can be expected due to the reduction of processes.

[0015]

EXAMPLES The present invention will be described in detail below with reference to examples. Evaluation method of warpage on all sides The criteria for judging warpage are as follows. Warpage was evaluated using a three-dimensional measuring instrument (Mitoyo Seisakusho). ◯: Curvature radius R of the warped portion is 10,000 mm or more Δ: Curvature radius R of the warped portion is 5000 mm or more and less than 10000 mm ×: Curvature radius R of the warped portion is less than 5000 mm Single sheet The amount of swelling of the part The amount of swelling (mm) was measured by using a caliper to measure the height of the swelling part from the plane of the sheet.

Examples 1 to 3 Polycarbonate resin sheet having a thickness of 0.5 mm (hereinafter,
(PC sheet) has light-transmissive numbers and marks printed in the center, and light-shielding topcoat printing is applied to the other parts, and then the sheet is pressed with a press machine according to the dimensions of the die mounting part. Punched out. A mold having a fixed core (diameter 102 mmφ) on the cavity side and a movable core (diameter 96 mmφ) having cushioning property on the core side, as shown in FIG. 1. The shape of the box was conical, the movable side was flat, and the sheet was sandwiched so that it would not be laminated with the molding resin when the mold was closed. The mold cavity has a thickness of 3 mm at the portion laminated with the resin, 130 mm in the parallel direction from the film gate, and 400 mm in the vertical direction.
Is a partially three-dimensional mold for illuminated nameplate.

Next, as shown in FIG. 2, the core side and the movable side core were moved forward to close the mold, and the seat was sandwiched by the cushioning core. Then, in the injection step, a molten glass fiber-containing polycarbonate resin molding material shown below was injected and injected as shown in FIG. Example 1 Mitsubishi Gas Chemical Co., Inc .: trade name: Iupilon GS-2020M glass fiber blending ratio: 20% by weight, molding shrinkage: 0.1
% Example 2 Mitsubishi Gas Chemical Co., Inc .: trade name: Iupilon GS-2030M glass fiber blending ratio: 30% by weight, molding shrinkage: 0.1
% Example 3 Mitsubishi Gas Chemical Co., Inc .: trade name: Iupilon GS-2050M glass fiber blending ratio: 50% by weight, molding shrinkage: 0.0
5%

The above injection is performed under the conditions of a resin temperature of 310 ° C., a mold temperature of 60 ° C., and a pressure of 1600 kgf / cm ² , and injection injection is performed except the portion sandwiched by the cores as shown in FIG. The PC sheet and the molding material were integrated as they were into a mold shape, and the portion sandwiched between the cores was a flat sheet because it was not laminated with the resin.
The PC sheet was free from wrinkles and the surface printing was not disturbed. In addition, there was no warp on the entire surface of the molded product, and no swelling of the flat sheet single part. In addition, an illuminated nameplate product having a sharp edge on the aperture and a light-shielding property on the light-shielding portion was obtained. The evaluation results are shown in Table 1.

Comparative Examples 1 and 2 Similar to Examples 1 to 3, different materials having different molding shrinkage ratios were used and injection molding was performed in the same manner, and comparison was made between the warp of the product and the swelling state of the sheet not laminated with the resin. I went. Comparative Example 1 Mitsubishi Gas Chemical Co., Ltd .: trade name: Iupilon S-3000 Glass fiber blending ratio: 0% by weight, molding shrinkage: 0.5% Comparative Example 2 Mitsubishi Gas Chemical Co., Ltd .: trade name: Iupilon GS-2010M glass fiber blending ratio: 10% by weight, molding shrinkage: 0.3
The evaluation results are shown in Table 2.

[0020]

[Table 1] Example No. 1 2 3 State of warpage on the entire surface ○ ○ ○ Swelling amount (mm) of single sheet portion 2.10 1.31 0.74

[0021]

[Table 2] Comparative Example No. 1 2 3 State of warpage of the entire surface × Δ Δ Swelling amount (mm) of single sheet portion 3.76 2.77 3.76

[0022]

EFFECTS OF THE INVENTION The molded product molded by the manufacturing method of the present invention can be obtained as a three-dimensional molded product with less deformation such as warpage and waviness and excellent appearance. Further, the sheet used in the present invention had no printing disorder in the molded product even if it was printed and coated. Further, even when an illumination nameplate having a printed light-shielding portion that is not laminated is formed, when the portion that is not laminated is provided, the illuminated portion has an excellent appearance.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a state in which a sheet is attached to a fixed core in a manufacturing process of a laminated molded product.

FIG. 2 shows a state in which a sheet is sandwiched between a fixed core and a movable core in a manufacturing process of a laminated molded product.

FIG. 3 shows a state in which a thermoplastic resin (A) is injected and injected into a cavity in a manufacturing process of a laminated molded product.

[Explanation of symbols]

 1: Sheet made of thermoplastic resin (S) 2: Thermoplastic resin (A) 3: Cavity side 4: Core side 5: Fixed side core 6: Movable side core

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location // B29K 69:00 105: 06 (72) Inventor Hisashi Tahara 5-6 Higashi-Hachiman, Hiratsuka-shi, Kanagawa No. 2 Sanritsu Gas Chemical Co., Ltd. Plastics Center

Claims (5)

[Claims] 1. A thermoplastic resin (S) cut into a predetermined shape.
The manufactured sheet is mounted in the mold cavity, and the thermoplastic resin (S) and the thermoplastic resin (A) that can be welded are injection-injected onto the sheet in the cavity to form a planar or three-dimensional integrally molded product. Is a molding shrinkage in the direction parallel to the sheet surface as a thermoplastic resin (A) when a molded product is obtained by using a 4-inch disc die having a thickness of 3.2 mm. The value obtained from the formula 100 × (die size-formed product size) / (die size) is 0.
A method for producing a synthetic resin molded article, which comprises using 1% or less of a resin or a resin composition. 2. The method for producing a synthetic resin molded article according to claim 1, wherein the sheet made of the thermoplastic resin (S) is a sheet to which characters, marks are added or decorated by printing, painting or hot stamping in advance. 3. A mold in which a movable core having a cushioning property is mounted on a cavity core side, and a part of a thermoplastic resin (S) sheet mounted in the mold cavity is covered with the core. After that, the thermoplastic resin (A) is injection-molded in the cavity to form a portion in which the thermoplastic resin (A) is not laminated, the method for producing a synthetic resin molded product according to claim 1. . 4. The method of manufacturing a synthetic resin molded product according to claim 3, wherein a cylinder mechanism or a conduction motor mechanism that is driven by at least a spring, air, water, or hydraulic oil is used to operate the core or the cavity. A method for producing a synthetic resin molded article, which is characterized in that the method is used. 5. The thermoplastic resin (S) is a polycarbonate resin, and the thermoplastic resin (A) is 20 in the resin composition.
The method for producing a synthetic resin molded article according to claim 1, which is a polycarbonate resin composition containing -50% by weight of glass fiber.