JPH07186156A - Mold for synthetic resin material and others - Google Patents

Abstract

PURPOSE:To provide a mold with a film having improved mold release characteristics, water repellency, oil repellency, lubricating properties, etc., by using a film prepd. by means of an electroless composite plating method. CONSTITUTION:A mold for molding a synthetic resin material, etc., is prepd. by a method wherein a base material for the mold is immersed in a plating bath wherein fluororesin particles with characteristic shape and dimension are dispersed and electroless plating is performed to co-deposit the fluororesin particles on the surface of the base material of the mold.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a mold for molding a synthetic resin material, more specifically, silicone rubber, urethane, epoxy,
The present invention relates to a molding die used for molding a synthetic resin material such as ABS.

[0002]

2. Description of the Related Art Conventionally, a hard chrome plating is generally applied to the surface of a mold used for molding a synthetic resin material such as silicon rubber, urethane, epoxy, ABS or the like. This hard chrome plating has a high coating hardness and excellent wear resistance, but on the other hand, it not only increases the cost but also has a problem that the uniform electrodeposition is inferior depending on the shape and the precision of the molded product is low. . In addition, the mold release property is poor, and therefore it is necessary to apply a mold release agent every day, which reduces work efficiency and adversely affects the product, and also causes problems such as the destruction of the ozone layer due to CFCs contained in the mold release agent. There was such a thing.

From such a background, as a method of improving the mold releasability and improving the working efficiency, it is considered to form a film on the surface of the mold by using a fluororesin releasing agent. Known methods include a method of uniformly coating and baking a fluororesin-based release agent, and a dispersion plating method using a plating bath in which fine particles of a fluororesin having an average particle diameter of 1 μm or less are dispersed.

[0004]

By the way, in the method of coating and baking the above-mentioned fluororesin-based mold release agent, the mold releasability is improved, but there is a problem in durability. In other words, the molding of several tens of shots results in a poor mold release, resulting in a decrease in productivity. On the other hand, even when the latter dispersion plating method is used, the durability is slightly improved as compared with the former method, but there is a problem in that the mold releasability becomes poor after about several hundred shots and it cannot be put to practical use.

[0005]

The present invention has been made to solve the above-mentioned problems of the prior art, in which electroless plating is performed by immersing a substrate in a plating bath in which fluororesin particles are dispersed. By doing so, a mold for molding a synthetic resin material or the like in which the fluororesin particles are co-deposited on the surface of the base material is provided.

The fluororesin particles have a molecular weight of 80.
An aspherical shape having a median diameter of 1 to 30 μm
Preferably, a short fiber shape is used and the dispersion amount is 50 g /
It is adjusted to be from liter to 500 g / liter.

[0007]

[Operation] According to the molding die of the synthetic resin material or the like having the above structure, the fluororesin particles protruding on the coating film are sufficiently firmly fixed by the plating metal, so that the mold releasability is maintained for a long period of time.

[0008]

[Example] The electroless plating solution used in the present invention is preferably an electroless nickel plating bath, but other electroless copper plating solutions, electroless tin plating solutions, etc. capable of electroless composite plating It goes without saying that there is no particular limitation so long as it is. Further, the mold base material is not particularly limited, and steel, copper, stainless steel, aluminum, magnesium, cast iron, zinc and alloys of these metals, and catalyst-added resins, ceramics and the like can be used.

Polytetrafluoroethylene particles are preferably used as the fluororesin particles used in the present invention, but it goes without saying that they are not particularly limited as long as they are particles of a resin having fluorine atoms on the surface. As conditions for high-density co-deposition, the molecular weight of the fluororesin particles is preferably in the range of 8,000 to 200,000 as a polymer, and particularly preferably 10,000 to 50,000.

The median diameter of the fluororesin particles is 1 μm.
It is necessary to be 30 μm, and those having a thickness of 1 μm to 10 μm are preferably used. Further, the shape of the fluororesin particles is a non-spherical indefinite shape, or preferably a short fiber-like slightly elongated shape even if it is not required to be cylindrical, and each particle at the time of eutectoid is Due to the polar effect of the covering surfactant, they repel each other and are attracted to the surface, and as a result, the particles are taken into the coating while standing as if they were flocked to the surface.

As a result, the particles can be co-deposited at a high density, the adhesion to the matrix metal is improved, and more fluid parts are formed on the surface by the heat treatment described later, and the resin layer on the surface is formed. Since the thickness increases, the durability and other effects are improved. Therefore, it is important that the particles have an aspherical shape, particularly a short fiber shape. In the present invention, the addition amount of the fluororesin particles to the electroless plating bath needs to be dispersed in an amount of 50 g or more per liter of the liquid, and particularly under the condition of 100 g / liter or more, releasability and water repellency The effects such as oil repellency are increased. However, if the addition amount is too much, the effect does not increase so much, and if the cost and the work at the time of making the plating bath are taken into consideration, it is at most 500.
The practical limit is up to g / liter, and the addition amount is 100 g.
The condition of / liter to 200 g / liter is preferably used.

Also, since the fluororesin particles have high water repellency,
In order to uniformly disperse the particles in the plating bath, a cationic surfactant is used according to a conventional method. Such known surfactants are not particularly limited, but include quaternary ammonium salts, secondary / tertiary amines, indazolines, polyoxyethylene-based, polyethyleneimine-based, ester-based and carboxylic acid-based surfactants. , Sulfonic acid type and the like are exemplified.

The heat treatment in the present invention is a preferable step in order to further improve the effects such as releasability and water / oil repellency of the coating film obtained by electroless plating. By the heat treatment at 300 ° C. or higher, the fluororesin particles on the surface have fluidity, and the particles themselves spread and overlap each other, so that the surface is covered with the fluororesin with a higher density.

For this phenomenon, 300 ° C. or higher and 400
Heat treatment at or below ℃ is required, but the higher the treatment temperature, the greater the amount of loss due to evaporation of the fluororesin on the surface.
Heat treatment in an inert atmosphere is preferably used in the range of 320 ° C. or higher and 350 ° C. or lower, which is the glass transition point of the fluororesin. Further, when an electroless nickel plating bath is used for manufacturing the coating, the coating increases its Vickers hardness to about Hv600 by heat treatment, and is more effective for application to molding machine parts and dies.

Next, an example of an experiment conducted by the present inventor will be shown. Experimental Examples (1 to 3) A nickel plating bath having the following composition was used as a base composition. Nickel chloride: 30 g / liter Sodium hypophosphite: 10 g / liter Sodium hydroxyate: 50 g / liter Water: Remainder 50 Polytetrafluoroethylene particles (median diameter 6 μm or less referred to as PTFE particles) in the adjusted plating bath,
It was added at a concentration of 130,200 (g / liter) and was dispersed by using an appropriate amount of a cationic surfactant (fourth feed ammonium salt system) according to the amount of PTFE particles.

As a test die for a simple peeling test, material S45C, dimensions 100 mm long, 100 mm wide, 20 mm thick
Electroless plating treatment was performed using the above-prepared three types of plating solutions.
Containing electroless plating solution (Kaniflon made by Kanigen Japan)
Was used to perform a plating treatment to produce a comparative mold. As the electroless plating treatment, first, as a pretreatment, the test mold is preliminarily subjected to solvent degreasing and alkali degreasing (50 ° C. × 5 minutes).
Then, the surface was activated with 10 vol% hydrochloric acid (normal temperature × 2 minutes) for scale removal. Next, 10 liters of the plating solution was placed in a stainless steel pad, and the plating solution was immersed in a stirrer for 1 hour at a bath temperature of 90 ° to perform electroless plating.

As a method of the peeling test, first, a dimension of 50 mm in width and 50 in width is provided between the above-mentioned three kinds of test dies and the comparative dies.
mm, 2 mm thick vulcanized silicone rubber scissors, 150 ℃ ~
Heat to 180 ℃, press, open the mold after cooling,
It was confirmed which side the silicone rubber adhered to. The above peeling test was repeated for each of the three types of molds described above, and each 200 times.
The test was repeated 200 times, and the results are shown in Table 1.

Experimental Examples (4 to 20) Next, as a test for determining the dispersion concentration, the above Experimental Examples 1 to 3 were conducted.
In the same manner as above, the PTFE particles were added to the plating bath as O, 20, 40, 5
0, 60, 90, 100, 110, 130, 150, 1
70, 190, 200, 250, 300, 400 and 5
It was added at a concentration of 00 (g / liter) and dispersed. Further, as the test die for plating, the material S45C,
Using the same shape having dimensions of 250 mm in length, 250 mm in width, and 30 mm in thickness, electroless plating was performed in the same manner as in Experimental Examples 1 to 3 above.

The test mold surface thus obtained is measured for releasability and contact angle with water (hereinafter referred to as contact angle), and the results are shown in Table 2 together with the plating conditions. The mold releasability was measured by the number of times until a mold release defect occurred in the molding of silicon rubber. The contact angle was measured at room temperature using a contact angle measuring device. Comparative Example 1 As a comparative example, a plating process was performed using the above-mentioned commercially available PTFE-containing electroless plating solution to prepare a comparative mold, and the same test was conducted. The results are also shown in Table 1.

Experimental Example (21 to 31) The compounding concentration of the PTFE particles used in Experimental Example 8 was 130 g /
For a liter plating bath, the plating bath temperature is 90 ° C,
The plating was performed by changing the temperature to 85 ° C, 80 ° C and 75 ° C. The plating time was 0.5, 1 and 2 hours. Regarding the surface of the obtained test mold, the above Experimental Example 4 to
In the same manner as in Example 20, mold release and contact angle were measured. The measurement results are shown in Table 3.

Further, the above-mentioned Experimental Examples 8, 12, 15 and 19
Heat treatment was performed on the test mold manufactured under the conditions of, and hardness, releasability and contact angle were measured. The heat treatment temperatures were 320 ° C and 350 ° C. The results of these experiments are shown in Table 3 together with the plating conditions, and the hardness was measured with a micropickers hardness meter at a load of 20 g. Table 1
Therefore, the superiority of the surface releasability by this method was clarified.

Further, as is clear from Table 2, when the PTFE addition amount exceeds 50 g / liter, the shot number is improved,
When the amount exceeds 100 g / liter, the water repellency is remarkably increased, and the releasability far exceeds the conventional 600 shots of the electroless plating surface. Further, as is clear from Table 3, the bath temperature affects the growth rate of the coating, but the characteristics of the coating are not significantly affected.

As to heat treatment, as is clear from Table 4, the hardness and the number of shots are improved from those of 320 ° C. by the method of heat treatment at 350 ° C.
It was found that the heat treatment at ℃ was good, and the heat treatment at 350 ℃ markedly deteriorated.

[0024]

According to the present invention, the following remarkable effects are achieved. (1) Since the fluororesin particles present on the protrusions on the electroless plating film are sufficiently firmly fixed by the plating metal, the film has much better adhesion than the conventional resin coating. The effect of releasability, water repellency, oil repellency, etc. is maintained over a long period of time. Therefore, it was possible to perform molding a large number of times as compared with the conventional synthetic resin molding die.

(2) Since the electroless plating is used for forming the coating and the characteristics of the electroless plating are used as they are, a coating having a uniform thickness can be formed without being affected by the shape of the die base material. A mold that can be formed and has excellent releasability can be obtained. (3) By heat treatment, the surface of the coating is covered with fluororesin with higher density, and the effects of release agent, water repellency, oil repellency, etc. are further maintained, and an electroless nickel plating bath is used. Then, the heat treatment increases the hardness of the matrix metal to about Hv600. This coating can be suitably used, for example, in molding machine parts and molds.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

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[Procedure amendment]

[Submission date] July 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Mold for molding synthetic resin material, etc.

[Claims]

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a mold for molding a synthetic resin material, more specifically, silicone rubber, urethane, epoxy,
The present invention relates to a molding die used for molding a synthetic resin material such as ABS.

[0002]

Conventionally, silicone rubber, urethane, epoxy, generally hard Shitsuku Romumekki can be applied to a surface of a mold used when molding the synthetic resin material such as ABS. The hard chrome plating, high target film hardness, while having excellent abrasion resistance, poor throwing power depending on the shape not only the cost is high, there is a problem of low accuracy of the formed products . In addition, poor releasing property, ho for the
Pot must be applied each time the releasing agent, onto a negative impact on the reduction and product efficiency, was also problems such as destruction of the ozone layer by CFCs contained in the release agent spray.

From such a background, as a method of improving the mold releasability and improving the working efficiency, it is considered to form a film on the surface of the mold by using a fluororesin releasing agent. Known methods include a method of uniformly coating and baking a fluororesin-based release agent, and a dispersion plating method using a plating bath in which fine particles of a fluororesin having an average particle diameter of 1 μm or less are dispersed.

[0004]

By the way, in the method of coating and baking the above-mentioned fluororesin-based mold release agent, the mold releasability is improved, but there is a problem in durability. In other words, the molding of several tens of shots results in a poor mold release, resulting in a decrease in productivity. On the other hand, even when the latter dispersion plating method is used, the durability is slightly improved as compared with the former method, but there is a problem in that the mold releasability becomes poor after about several hundred shots and it cannot be put to practical use.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is characterized by
For molding synthetic resin materials, etc. in which the fluororesin particles are co-deposited on the surface of the base material by immersing the base material in a plating bath in which fluororesin particles having various shapes and dimensions are dispersed and electroless plating It is intended to provide a mold.

The fluororesin particles have a molecular weight of 80.
00- 200,000, and non-spherical median size 1 to 30 [mu] m, preferably the dispersion amount short fibrous form is used 50
It is adjusted to be g / liter to 500 g / liter.

[0007]

[Operation] According to the molding die of the synthetic resin material or the like having the above structure, the fluororesin particles protruding on the coating film are sufficiently firmly fixed by the plating metal, so that the mold releasability is maintained for a long period of time.

As the electroless plating solution used in the present invention, an electroless nickel plating bath can be preferably used, but other electroless copper plating solutions, electroless tin plating solutions and the like can be used as well. It goes without saying that there is no particular limitation. Further, the mold base material is not particularly limited, and steel, copper, stainless steel, aluminum, magnesium, cast iron, zinc and alloys of these metals, and catalyst-added resins, ceramics and the like can be used.

Polytetrafluoroethylene particles are preferably used as the fluororesin particles used in the present invention, but it goes without saying that they are not particularly limited as long as they are particles of a resin having fluorine atoms on the surface. As conditions for high-density co-deposition, the molecular weight of the fluororesin particles is preferably in the range of 8,000 to 200,000 as a polymer, and particularly preferably 10,000 to 50,000.

The median diameter of the fluororesin particles is 1 μm.
It is necessary to be 30 μm, and those having a thickness of 1 μm to 10 μm are preferably used. Further, the shape of the fluororesin particles is a non-spherical indefinite shape, or preferably a short fiber-like slightly elongated shape even if it is not required to be cylindrical, and each particle at the time of eutectoid is in the plating bath. will be attracted to the surface while repelling each other by the action of the polarity of a surfactant for covering the particle concentration and the particle, as a result, the film in a state standing as flocked to the surface many particles It will be taken in.

As a result, the particles can be co-deposited at a high density, the adhesion to the matrix metal is improved, and more fluid parts are formed on the surface by the heat treatment described later, and the resin layer on the surface is formed. Since the thickness increases, the durability and other effects are improved. Therefore, it is important that the particles have an aspherical shape, particularly a short fiber shape. In the present invention, the addition amount of the fluororesin particles to the electroless plating bath needs to be dispersed in an amount of 50 g or more per liter of the liquid, and particularly under the condition of 100 g / liter or more, releasability and water repellency The effects such as oil repellency are increased. However, if the addition amount is too much, the effect does not increase so much, and if the cost and the work at the time of making the plating bath are taken into consideration, it is at most 500.
The practical limit is up to g / liter, and the addition amount is 100 g.
The condition of / liter to 200 g / liter is preferably used.

Also, since the fluororesin particles have high water repellency,
In order to uniformly disperse the particles in the plating bath, a cationic surfactant is used according to a conventional method. Although not particularly limited as such known surface active agents, quaternary ammonium salts, second and third amines, Lee Mi <br/> Dazorin, polyoxyethylene-based, polyethyleneimine-based, Examples thereof include ester type, carboxylic acid type and sulfonic acid type.

The heat treatment in the present invention is a preferable step in order to further improve the effects such as releasability and water / oil repellency of the coating film obtained by electroless plating. By the heat treatment at 300 ° C. or higher, the fluororesin particles on the surface have fluidity, and the particles themselves spread and overlap each other, so that the surface is covered with the fluororesin with a higher density.

For this phenomenon, 300 ° C. or higher and 400
Heat treatment at or below ℃ is required, but the higher the treatment temperature, the greater the amount of loss due to evaporation of the fluororesin on the surface.
Heat treatment in an inert atmosphere is preferably used in the range of 320 ° C. or higher and 350 ° C. or lower, which is the glass transition point of the fluororesin. Further, when an electroless nickel plating bath is used for manufacturing the coating, the coating increases its Vickers hardness to about Hv600 by heat treatment, and is more effective for application to molding machine parts and dies.

[0015]

Example shows an embodiment of the present invention will now have conducted. Experimental Examples (1 to 3) A nickel plating bath having the following composition was used as a base composition. Nickel chloride: 30 g / liter Sodium hypophosphite: 10 g / liter Sodium hydroxyate: 50 g / liter Water: Remainder Polytetrafluoroethylene particles (referred to as PTFE particles having a median diameter of 6 μm or less) in the adjusted plating bath are 5
Add at a concentration of 0,130,200 (g / l),
Cationic surface active agent (quaternary ammonium salt type)
An appropriate amount was used according to the amount of TFE particles and dispersed.

As a test die for a simple peeling test, material S45C, dimensions 100 mm long, 100 mm wide, thickness 2
Using a 0 mm flat plate, electroless plating treatment was performed with the above-prepared three kinds of plating liquids, and a similar flat plate was plated with a commercially available PTFE-containing electroless plating liquid (Kaniflon made by Japan Kanigen Co., Ltd.) for comparison. Then, a comparative mold was produced. As the electroless plating treatment, first, as a pretreatment, solvent degreasing and alkali degreasing (50
℃ × 5 minutes), then 10V for scale removal
The surface was activated using ol% hydrochloric acid (normal temperature × 2 minutes). Then placed plating liquid 10 liters of a stainless bar Tsu DOO, while stirring the plating liquid by a stirrer bath temperature 90 ° C.
It was soaked for 1 hour for electroless plating.

As the method of the peeling test, first, between the above-mentioned three kinds of test dies and the comparative dies, the dimension is 50 mm in length and 5 in width.
Insert 0 mm, 2 mm thick vulcanized silicone rubber between 1
It was heated to 50 ° C. to 180 ° C., pressed, cooled, and the mold was opened to confirm which side the silicon rubber adhered to. The peeling test, tries each 200 times repeatedly with the three mold above. The results are shown in Table 1.

Experimental Examples (4 to 20) Next, as a test for determining the decomposition concentration, the above Experimental Examples 1 to 3 were conducted.
In the same manner as above, the PTFE particles were added to the plating bath at 0 , 20, 4
0, 50, 60, 90, 100, 110, 130, 15
0,170,190,200,250,300,400
And 500 (g / liter) to add and disperse. Further, as the test die for plating, the material S4 is used.
5C, dimensions length 250mm, width 250mm, thickness 30mm
The same shape was used for electroless plating in the same manner as in Experimental Examples 1 to 3.

The test mold surface thus obtained was measured for releasability and contact angle with water (hereinafter referred to as contact) , and the results are shown in Table 2 together with the plating conditions. The mold releasability was measured by the number of times until a mold release defect occurred in the molding of silicon rubber. The contact angle was measured at room temperature using a contact angle measuring device. Comparative Example 1 As a comparative example, a plating process was performed using the above-mentioned commercially available PTFE-containing electroless plating solution to prepare a comparative mold, and the same test was performed. The results are also shown in Table 2 .

Experimental Example (21-31) Compounding concentration 13 of the PTFE particles used in Experimental Example 12 above
For 0 g / l plating bath, set the plating bath temperature to 9
The plating was performed by changing the temperature to 0 ° C, 85 ° C, 80 ° C and 75 ° C. The plating time was 0.5, 1 and 2 hours. Regarding the surface of the obtained test mold, the above-mentioned Experimental Example 4 was used.
It was measured release property and contact angle in the same manner as 20. The measurement results are shown in Table 3.

Further, the above-mentioned Experimental Examples 8, 12, 16 and 19
Heat treatment was performed on the test mold manufactured under the conditions of, and hardness, releasability and contact angle were measured. The heat treatment temperatures were 320 ° C and 350 ° C. The results these experiments are shown together with the plating conditions shown in Table 4, and the hardness was measured under a load 20g by microbeads Vickers hardness tester. Table 1
The superiority of the surface releasability by this method was clear.

Further, as is clear from Table 2, when the amount of PTFE added exceeds 50 g / liter, the shot number is improved, and when it exceeds 100 g / liter, the water repellency is remarkably increased and the releasability is also conventional. The result was far more than about 600 shots of the surface of electroless plating. Further, as is clear from Table 3, the bath temperature affects the growth rate of the coating, but the characteristics of the coating are not significantly affected.

[0023] Also, as is clear from Table 4 for the heat treatment, hardness, number of shots is better in heat treatment at 350 ° C. than 320 ° C. is more improved, the water repellent 320
It was found that the heat treatment at ℃ was good, and the heat treatment at 350 ℃ markedly deteriorated.

[0024]

According to the present invention, the following remarkable effects are achieved. (1) Since the fluororesin particles present in the projection shape on the electroless plating film are sufficiently firmly fixed by the plating metal, the film has much better adhesion than the conventional resin coating. The effect of releasability, water repellency, oil repellency, etc. is maintained over a long period of time. Therefore, it was possible to perform molding a great number of times as compared with the conventional synthetic resin molding die.

(2) Since the electroless plating is used for forming the coating and the characteristics of the electroless plating are used as they are, a coating having a uniform thickness can be formed without being affected by the shape of the die base material. A mold that can be formed and has excellent releasability can be obtained. (3) By heat treatment, the surface of the coating is covered with fluororesin with higher density, and the effects of release agent, water repellency, oil repellency, etc. are further maintained, and an electroless nickel plating bath is used. In that case, the heat treatment raises the hardness of the matrix metal to about Hv600. This coating can be suitably used, for example, in molding machine parts and molds.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

Claims (4)

[Claims] 1. The fluororesin particles are co-deposited on the surface of the die substrate by immersing the die substrate in a plating bath in which the fluororesin particles are dispersed and performing electroless plating. Mold for molding synthetic resin materials. 2. The fluororesin particles according to claim 1, which are non-spherical having a molecular weight of 8,000 to 200,000 and a median diameter of 1 to 30 μm. 3. The plating bath according to claim 1, wherein the fluororesin is dispersed in an amount of 50 to 500 grams per liter. 4. A mold base is immersed in a plating bath in which fluororesin particles are dispersed, and electroless plating is performed to co-deposit the fluororesin particles on the surface of the base, and then the mold base is formed. A method for manufacturing a metal mold for forming a synthetic resin material or the like, which comprises heating the material surface to 300 ° C to 400 ° C to perform heat treatment.