JP3729927B2 - Resin composition for vacuum mold and method for producing vacuum mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a porous vacuum molding resin composition used for molding a plastic product having a complex pattern such as a wrinkle pattern on a surface by adhering a molding object to the mold by adsorption , and a method for producing a vacuum molding mold. .
[0002]
[Prior art]
Conventionally, as this type of mold, there have been used a number of small-diameter holes drilled on the surface of an epoxy resin, an electroformed plate or the like, and these are made into vacuum molds as vent holes.
[0003]
However, drilling with a drill requires a high level of processing technology and a great amount of processing time, and requires a skilled engineer, resulting in a high mold manufacturing cost. In addition, since the mold that has been drilled in this way is difficult to uniformly adsorb over the entire molding surface, the pressure applied to the product that is the molding object during molding becomes uneven, and the complex pattern of the product is blurred. In addition, the quality of the finished product deteriorates, and drill holes (pitch φ0.2 at 5 to 10 mm intervals) are transferred.
[0004]
[Problems to be solved by the invention]
In order to solve such a problem, various molds using a porous material having air permeability have been proposed. However, such a conventional mold using a porous material has a problem of durability due to insufficient strength of the surface layer (hereinafter referred to as gel coat), generation of defective products due to large bubbles (diameter of 0.5 mm or more) on the surface, etc. Because of various problems, it has been difficult to provide a mold that can withstand practical use.
[0005]
The present invention has been made in view of the above points, and the object of the invention is a porous material that can be uniformly adsorbed, has sufficient strength to withstand practical use, no large bubbles, and An object of the present invention is to provide a low-cost resin composition for vacuum molding and a method for producing a vacuum molding die .
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an epoxy resin having a viscosity of at least 100000 cps (25 ° C.), a curing agent for the epoxy resin, a first aluminum powder having a particle length of about 50 to 120 μm, and a particle size of about A vacuum molding resin composition containing a second aluminum powder having an oxide film on the surface at 10 μm or less.
[0007]
The mixing ratio of the epoxy resin, the first aluminum powder, and the second aluminum powder is about 70 to 80 parts of the first aluminum powder and about 0 of the second aluminum powder with respect to 100 parts of the epoxy resin. .5 to 5 parts.
[0008]
The first aluminum powder has a ratio of the minor axis to the major axis, that is, the minor axis / major axis is 1/5 or less.
[0009]
Alternatively, at least an epoxy resin having a viscosity of 100,000 cps (25 ° C.) or less, a curing agent for the epoxy resin, a first aluminum powder having a particle length of about 50 to 120 μm, and an oxide film on the surface having a particle size of about 10 μm or less. A resin composition for a vacuum mold containing a second aluminum powder is provided as a first layer on the mold, and a third aluminum powder is sprayed thereon to be cured as a second layer. A back-up material is provided as a third layer in a method for manufacturing a vacuum forming mold.
[0010]
The first layer is a vacuum mold resin composition of about 0.5 mm, and the second layer is a layer of about 0.7 mm by spraying a third aluminum powder having a particle size of about 120 to 300 μm. The third layer is composed of a fourth aluminum powder having a particle size of about 300 to 1000 μm, an epoxy resin, and a curing agent for the epoxy resin, and the fourth aluminum powder is about 450 to 700 with respect to the epoxy resin 100. It was decided to be a backup material made by mixing parts.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described. An epoxy resin having a viscosity of 100000 cps (25 ° C.) or less is used as the gel coat material for the mold. When the viscosity is 100,000 cps or more, a uniform gel coat is not obtained and good results cannot be obtained. The type of this epoxy resin is not particularly limited, but it is desirable that the main component is a diglycidyl ether type epoxy resin of bisphenol A in consideration of workability, room temperature curability, physical properties after curing, and the like.
[0012]
The epoxy resin curing agent is not particularly limited, but aliphatic polyamines, modified aliphatic polyamines, and the like are excellent in terms of room temperature curability and physical properties after curing.
[0013]
The first aluminum powder mixed with the epoxy resin has a particle length of 50 to 120 μm. When the particle length exceeds 120 μm, the strength of the gel coat is reduced, and air bubbles having a diameter of 0.5 mm or more are easily formed on the surface of the mold, making it difficult to obtain a good molded product. The table | surface which compared the characteristic of the gel coat using particle | grain length 50-120 micrometers and aluminum powder out of this range in FIG. 4 is shown. The first aluminum powder can obtain a sufficient strength and air permeability by using an elongated product obtained by a predetermined processing operation. That is, a good characteristic is obtained when the ratio of the minor axis to the major axis of the first aluminum powder, that is, the minor axis / major axis is 1/5 or less, and the ratio of the minor axis to the major axis is 1/5 or more. And sufficient strength and breathability cannot be obtained.
[0014]
The second aluminum powder mixed with the epoxy resin preferably has a particle size of 10 μm or less and an oxidized surface. That is, when the surface of the aluminum powder is not oxidized, the aluminum aggregates and does not uniformly disperse, resulting in insufficient gel coat strength and air permeability. Then, by mixing the first aluminum powder and the second aluminum powder, the second aluminum powder adheres to the periphery of the first aluminum powder and is integrated.
[0015]
About 70 to 80 parts of the first aluminum powder and about 0.5 to 5 of the second aluminum powder, respectively, with respect to 100 parts of the epoxy resin, the epoxy resin, the first aluminum powder and the second aluminum powder. The epoxy resin curing agent is mixed in an appropriate amount for use to obtain a vacuum mold resin composition. Although it can be used beyond this range, the variation in strength and air permeability increases. FIG. 5 shows the result of comparing the physical properties of the vacuum mold resin composition according to the present invention thus obtained and the gel coat other than the above blend ratio. As described above, the resin composition for a vacuum mold (gel coat) according to the present invention exhibits characteristics superior to gel coats of other compounding ratios in all aspects of bending strength, compressive strength, and impact strength.
[0016]
As a material for reinforcing the mold by performing a pressing operation similar to that of the conventional mold on the back surface of the vacuum forming mold, i.e., the gel layer, 100 parts of epoxy resin of the gel coating material for the mold, What mixed about 450-700 parts of 4th aluminum powder with a particle size of about 300-1000 micrometers is used. If the mixing ratio of the fourth aluminum powder is outside the above range, the physical properties are lowered. In use, an appropriate amount of the epoxy resin curing agent is mixed before use.
[0017]
In addition, it is also possible to use metal powder (iron, copper, titanium) or inorganic powder (silica, calcium carbonate, mica) instead of each aluminum powder or mixed (2-5 parts) to a part thereof. Although it is conceivable, only aluminum can provide excellent and uniform performance in all aspects of lightness, breathability and strength.
[0018]
FIG. 6 shows a table in which the physical properties of the gel coat according to the present invention and the conventional gel coat are relatively compared (the product of the present invention is taken as 100). As is apparent from this table, the gel coat according to the present invention has characteristics superior to conventional products in all aspects of bending strength, compressive strength, and impact strength.
[0019]
【Example】
Next, a method for manufacturing a vacuum forming mold according to the present invention will be described with reference to the drawings. FIG. 1 shows a state during the production of a vacuum forming die according to the present invention. In the figure, 1 is a wooden frame, 2 is a master model, 3 is a vinyl chloride sheet having a wrinkle pattern, 4 is a gel coat, 5 is a layer obtained by spraying aluminum powder on the gel coat, and 6 is a backup layer. The method will be described in detail below.
[0020]
(1) First, a master model 2 having the same shape as the product is prepared, and a vinyl chloride sheet 3 having the same pattern (texture pattern) as the outer surface of the product is placed on the master model 2. In this example, the master model 2 and the vinyl chloride sheet 3 are used in consideration of economy and convenience, but the master model 2 itself may be used with a pattern.
(2) Further, the vacuum forming mold resin composition is further applied to a thickness of about 0.5 mm to form a gel coat 4.
(3) Next, the third aluminum powder (particle size: about 120 to 300 μm) is sprayed to a thickness of about 0.7 mm with an air gun, and left to stand at room temperature for 4 to 5 hours to gel, and gel coat (spray layer) 5
(4) After the gel layer was cured, the backup resin was applied to a thickness of 30 to 100 depending on the shape and size of the mold to form the backup layer 6, which was in the state of FIG. 1 and cured at room temperature for 12 hours.
(5) Next, the wooden frame 1, master model 2, and vinyl chloride sheet 3 in FIG. 1 are removed, and several air suction holes 10 are placed on the surface of the backup layer 6. And a mold as a finished product shown in FIG. 2 was obtained.
[0021]
FIG. 3 shows an example of a product (airbag) formed using the vacuum forming mold thus manufactured. In the figure, 7 is a cover molded product and 8 is a wrinkle pattern. Compared to the vacuum mold according to the present invention and a conventional mold for producing the same product,
(1) The finished state of the molded product is a level that is practically acceptable for the conventional type, but a large number of drill hole transfers appear, whereas the vacuum forming die according to the present invention is such Excellent finish without holes.
(2) With respect to the vent holes of the mold, the conventional type is partially missing, but the vacuum forming mold according to the present invention is uniformly distributed over the entire surface.
Thus, it can be seen that the vacuum forming die according to the present invention is excellent.
[0022]
【The invention's effect】
As described above, with the resin composition for vacuum molds according to the present invention,
(1) Anyone can easily produce a mold without the need for skilled drilling.
(2) The transfer of the drill hole is eliminated, and the transfer of a complicated pattern such as a wrinkle pattern can be reliably performed.
(3) The mechanical strength of the mold is large and it is durable.
(4) A mold with a reverse gradient shape can also be manufactured.
(5) The cost can be significantly reduced by a series of steps from mold production to molding.
(6) Even if it is used for a long time, it is difficult to cause clogging due to suction.
(7) The production period is about 1/3 to 1/5 of the conventional one.
(8) Productivity improved by 50%.
(9) Since the ventilation holes are dense and the air permeability is good, the burden on the suction pump is greatly reduced.
It has effects such as.
[0023]
Moreover, the mixing ratio of the epoxy resin, the first aluminum powder, and the second aluminum powder is about 70 to 80 parts of the first aluminum powder and about 0.5 of the second aluminum powder with respect to 100 parts of the epoxy resin. By mixing at a rate of ~ 5 parts,
Necessary strengths such as bending, compressive strength and impact strength can be ensured while maintaining air permeability.
[0024]
Moreover, the 1st aluminum powder mixed with an epoxy resin makes the short diameter / major diameter 1/5 or less,
Sufficient strength and breathability as a gel coat can be exhibited.
[0025]
Alternatively, the manufacturing method of the present invention makes it possible to provide a vacuum forming mold that is an inexpensive porous material that can be uniformly adsorbed, has sufficient strength to withstand practical use, and does not have large bubbles. It was.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state of manufacturing a vacuum forming die according to the present invention.
2 is a cross-sectional view of the vacuum forming die obtained in FIG. 1. FIG.
3 is an external view of a cover molded product manufactured using the vacuum forming mold of FIG. 2. FIG.
[Figure 4] and the particle length 50 to 120 [mu] m, a table relative comparison of characteristics of the gel coat blended with other particle length aluminum powder of.
FIG. 5 is a table comparing the physical properties when the blending ratio of the epoxy resin and the first and second aluminum powders is changed from that of the invention product.
FIG. 6 is a table comparing the physical properties of a gel coat according to the present invention and a conventional gel coat.

Claims (5)

An epoxy resin having a viscosity of at least 100000 cps (25 ° C.), a curing agent for the epoxy resin, a first aluminum powder having a particle length of about 50 to 120 μm, and an oxide film on the surface having a particle size of about 10 μm or less. A resin composition for a vacuum mold, comprising: 2 aluminum powder.   The mixing ratio of the epoxy resin, the first aluminum powder, and the second aluminum powder is about 70-80 parts of the first aluminum powder and about 0.5 of the second aluminum powder with respect to 100 parts of the epoxy resin. The resin composition for a vacuum mold according to claim 1, which is ˜5 parts.   The resin composition for a vacuum mold according to claim 1 or 2, wherein the first aluminum powder has a minor axis / major axis of 1/5 or less. An epoxy resin having a viscosity of at least 100000 cps (25 ° C.), a curing agent for this epoxy resin, a first aluminum powder having a particle length of about 50 to 120 μm, and a second oxide having a particle size of about 10 μm or less and having an oxide film on the surface And a resin composition for a vacuum forming mold containing the aluminum powder as a first layer on the mold, sprayed with a third aluminum powder on the mold and cured as a second layer, and a backup thereon A method for producing a vacuum forming mold, comprising providing a material as a third layer. The first layer is a layer having a resin composition for vacuum molds of about 0.5 mm, the second layer is sprayed with a third aluminum powder having a particle size of about 120 to 300 μm to form a layer of about 0.7 mm, The third layer is a mixture of a fourth aluminum powder having a particle size of about 300 to 1000 μm, an epoxy resin, and a curing agent for this epoxy resin, and about 450 to 700 parts of the fourth aluminum powder with respect to the epoxy resin 100. The method for manufacturing a vacuum forming mold according to claim 4, wherein the backup material is a backup material.

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