JPS63307916A - Rim molding method for synthetic resin molded product - Google Patents

Abstract

PURPOSE:To lower the air flow resistance in a vent and prevent through-holes from getting clogged by injecting a reacting material into a mold main body having a number of through-holes constituted of micro non-electrodeposit sections, which are generated in the initial stage of electroforming, grown at the time of eletroforming and passed through between the front and rear faces, and carrying out the rim molding. CONSTITUTION:Mold main body 1 is formed by electroforming, and a number of through-holes 2 provided through the mold main body 1 are constituted of micro non-electrodeposit sections generated in the initial stage of electroforming and grown in the thickness direction at the time of electroforming, and the diameters of said through-holes are increased gradually from the surface of the mold main body 1 toward the back face. Desirably the maximum diameter of said through-holes 2 on the surface side of the mold main body 1 should be 0.1-0.5 mm, and the number of through-holes 2 should be 5-10000 per 10 cm<2> area of the mold main body 1 from the viewpoint of vacuum suction force. As the through-holes 2 are passed through by growing micro non-electrodeposit sections, air flow resistance in vacuum suction is low to carry out vacuum section more easily. Also, the through-holes 2 are seldom clogged and the inside of the through-holes 2 can be easily cleaned.

Description

DETAILED DESCRIPTION OF THE INVENTION Purpose of the Invention (Field of Industrial Application) This invention relates to a reaction injection molding method (hereinafter referred to as rim molding) for synthetic resin molded products using a porous mold formed by electroforming. ).

(Prior art and problems to be solved by the invention) The conventional rim molding method involves slowly injecting a reactive hardening resin into a mold at low pressure, and gas is usually vented during injection. . Gas handling holes for this purpose are formed between the dividing surfaces of both molds at appropriate locations on the outer periphery of the cavity, and communicate with the cavity.

However, these gas vent holes are not located on the entire inner surface of the cavity, but are formed only in areas where gas handling is particularly difficult, so depending on the shape of the molded product, gas venting may not be sufficient. Inadequate gas handling may cause cavities or burns in the molded product.

Therefore, by using a porous mold, the conventional gas handling holes are not only unnecessary, but also sufficient gas can be vented from the entire inner surface of the cavity.

Conventionally, in order to form a porous mold, the mold was molded using the old method to make it naturally porous, or the mold was formed by mixing water with a synthetic IM resin material, and then dehydrated to make it porous. The method of doing so was adopted.

However, in these methods, the holes are too small and it is difficult to vent gas, and the holes are not penetrating and are easily clogged, and cleaning the holes is also difficult.

In addition, a method of forming molds using electroforming, which is an applied technology of plating, was also adopted. This 7jF! One method will be briefly described below.

■ First, a conductive coating film, such as a spray solution containing a paste silver lacquer and a butyl acetate solution, is sprayed on the model to be electroformed (hereinafter referred to as the mandrel) to impart conductivity to the mandrel. do.

■ Next, add pure water! A pretreatment solution containing 1llI and stannous chloride is applied to the mandrel using a brush or the like to activate the surface of the mandrel and perform pretreatment to prevent the formation of pinholes.

■ Next, perform electroforming. The electrolytic solution used is one in which a nickel sulfamate solution and boric acid are mixed, and then a small amount of sodium lauryl sulfate, for example, is added as a surface active additive. This sodium lauryl sulfate prevents pinholes from forming in the electroformed layer on the surface of the mandrel during electroforming.

The electroformed material and the mandrel are immersed in the electrolyte stored in the electrolyte tank, the electrolyte is circulated, and the cathode rocker is operated to move the mandrel in the electrolyte. In the meantime, a current of 0.6 A per 100 CIII of the mandrel area is passed for 3 to 4 hours to electrodeposit a thin electroformed layer over the entire surface of the mandrel.

After confirming that the electroformed layer is thinly electrodeposited, apply the current to the mandrel surface! 14100cm! Convert to 1~2A per
Electroforming is continued to make the Wt electroformed layer smooth and finished into a desired shape, and the mandrel and WIJ layer are separated to form a mold body.

(2) A porous mold is completed by making a large number of small holes in the mold body formed as described above using a cone with a tip diameter of 0.3 IV or a laser beam.

However, even in the electroforming molds mentioned above, not only is the work of forming a large number of small holes extremely complicated, but in the case of molds with complex shapes, holes may be made transparent depending on the location. The problem was that it could not be done.

Therefore, even if gas handling is performed using such a mold, there is a problem that the gas handling is insufficient and the through holes become clogged, making it difficult to clean the insides of the through holes.

This invention was made in order to solve the above-mentioned problems, and its purpose is to form a rim that is easy to handle gas, is less likely to clog the through hole, and is easy to clean inside the through hole. The purpose is to provide a method.

Structure of the Invention (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a mold body formed by electroforming, in which minute non-electrodepositions generated in the early stage of electroforming are used. Inside the mold body, which has a large number of holes between the front and back surfaces, is grown during electroforming.
The method used was to inject a reactive material and form the rim.

(Function) At the time of injection, gas is handled through a large number of holes in the mold body. Since this through hole is penetrated by growing a minute non-electrodeposited portion, not only the airflow resistance when handling gas is lowered, but also the through hole is less likely to be clogged.

(Embodiment 1) Hereinafter, a first embodiment embodying the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a mold body according to the present invention, which is formed by electroforming. Reference numeral 2 denotes a large number of through holes provided through the i-type main body 1, and as will be described later, minute non-electrodeposited portions generated at the initial stage of the electroforming are removed in the thickness direction (metallic As shown in FIG. 3(b), the diameter gradually increases from the surface of the mold body 1 toward the reverse side. Although the shape of the through hole 2 is shown as a tapered shape as shown in FIG. 3(b), it goes without saying that the way it expands will vary depending on the electroforming conditions. For example, the inner surface of the through hole 2 may be uneven, or adjacent through holes 2 may be connected to each other.

The green diameter of this through hole 2 on the surface side of the mold body 1 is 0.
The thickness is preferably 1 to 0.5 mm. Vacuum suction power ^
On the one hand, this is to prevent any traces of the through holes 2 from remaining on the synthetic resin molded product. In addition, the number of through holes 2 is determined by the area of the mold body 1 10CIIIL in terms of vacuum suction force.
It is desirable to have 5 to 10,000 pieces per unit.

This mold body 1 is attached to an ND manufactured by Rim Molding, and the urethane reaction material FIW is melted and injected into the mold body 1. During this injection, the urethane reaction material W is added to the mold body 1.
Sufficient degassing is performed through the large number of through holes 2 over the entire surface, and fluidity is also improved.

Therefore, the synthetic resin material W can be reliably applied to the mold body 1.
It is possible to give the synthetic resin material W the shape of an uneven part for forming wrinkles and an uneven part for forming threads such as stitches by wearing the synthetic resin material W.

Moreover, since the through hole 2 is formed by growing a minute non-Wi-bonded portion, the air flow resistance during vacuum suction is low, and vacuum suction is easy to perform. Further, the through hole 2 is less likely to be clogged, and the inside of the through hole 2 can be cleaned easily. Furthermore, since the through holes 2 are formed at the same time as electroforming, there is no need to perform the process of forming the through holes 2 after electroforming, and the mold can be easily manufactured.

Further, the diameter of the through hole 2 of this embodiment gradually increases on the back side of the mold body 1 as electroforming progresses. Therefore, the diameter of the through hole 2 is sufficiently small on the front side of the mold body 1, so that not only no trace of the through hole 2 remains on the surface of the molded product, but also the diameter is large on the back side of the mold body 1. Therefore, the airflow resistance during vacuum suction is also lowered, and the suction force is increased, which is ideal for the mold.

That is, in conventional electroforming technology, pinholes occur irregularly and unstablely, and moreover, they appear largely on the surface, so they have been considered to be defects that must be avoided.

In contrast, in the present invention, the minute non-electrodeposited portions generated at the initial stage of electroforming are allowed to grow during the same electroforming process, and are made to penetrate through the holes to form minute through holes 2 that can be used for vacuum suction, etc., instead of pinholes. It is Tochino, and it can be said that it is an epoch-making mold that is based on an idea that is completely reversed.

In this way, the mold body 1 having a large number of through holes 2 formed by growing the minute non-electrodeposited portions generated at the initial stage of electroforming during electroforming can be used for RIM molding. ,
It is very effective in improving and maintaining vacuum suction power, making maintenance such as cleaning easier, and making mold manufacturing easier.

Next, the equipment, materials, etc. used to manufacture this mold body 1 will be explained.

3 is an electrolytic solution stored in the electrolytic solution tank A as shown in FIGS. 2(a) and (b), and is 450 (J/J!).
The electrolytic solution 3 consists of a nickel sulfamate solution and 40 (more than one) boric acid, the temperature of which is maintained at 37°C to 40°C. By adding 3.8 to 4.
It is adjusted to stay within the range of 2.

If the electrolyte 3 pill exceeds the above range, the cathode current efficiency that occurs during electroforming will decrease, and the pHtuf
This is because when t does not reach 3.8, basic precipitates are formed in the electrolytic solution 3, causing defects such as the electrolyzed metal becoming susceptible to discoloration.

Here, since the electrolytic solution 3 of this example does not contain a surfactant additive such as sodium lauryl sulfate, it has no effect of suppressing the formation of pinholes.

Therefore, non-ff1W portions (which were conventionally the seeds of pinholes) are likely to occur in the initial stage of electroforming, and the growth of through holes 2 is also promoted.

4 is a Mu material placed in the electrolyte 3, and in this embodiment nickel is used.

5 is a mandrel placed in the electrolytic solution 3 at a position facing the electroforming material 4, and is made of a synthetic resin material such as epoxy, acrylic, acrylic-butadiene-styrene copolymer, vinyl chloride, solid wax, metal, It is made of wood, ceramics, fabric, thread, etc. This mandrel 5 is a model of the mold body 1 shown in FIGS. 1 and 3(b), and is suspended from a cathode rocker 6 movably attached to the upper end of the electrolyte tank A. (b
), electrolysis occurs according to the movement of the can-dropper 6 in the longitudinal direction? It is designed to move back and forth within A3. Note that 7 is a moving device that drives the cathode locker 6 back and forth. Also, there is a w! outside of electrolyte tank A! sis is provided, the electroforming material 4 is applied to the anode, and the mandrel 5 is sprayed W! J8 are each electrically connected to the cathode.

Next, a method for manufacturing the mold body 1 will be explained in order.

(2) In order to make the mold body 1 porous, the mandrel 5 is subjected to a surface treatment process and a racking process before being immersed in the electrolytic solution 3.

First, in the surface treatment step, the surface of the mandrel 5 is polished with an abrasive such as a solvent or polishing powder to remove impurities attached to the surface and roughen the surface. The purpose of roughening the surface is to improve the compatibility of the conductive material and to improve the adhesion of the electroformed film. After this, mandrel 5
is washed with water to remove the abrasive on the surface, and then dried with jet air to complete the surface treatment process.

In the racking process, a spray liquid is applied to the desired surface of the mandrel 5 for electroforming to impart conductivity. This spray solution is made by mixing a paste silver lacquer (RC-10 manufactured by Fukuyama Metal Powder Co., Ltd. is used in this example) and a butyl acetate solution in a ratio of 1=1. It is made by mixing a vinyl chloride lacquer liquid in a proportion of 30% or less based on the total amount of the compounded liquid.

This spray liquid was sprayed twice until the surface of the mandrel 5 exhibited a complete metallic color, forming a spray layer 8 of approximately 15 μm or more on the surface of the mandrel 5, as shown in FIG. 3(a). , air dry the mandrel 5 for about 24 hours. Since the spray liquid contains a vinyl chloride lacquer liquid, the spray layer 8 on the surface of the mandrel 5 has low conductivity, and a large number of holes 2 are likely to be formed on the surface of the mandrel 5.

Looking at it more microscopically, spray 11218 not only has sM parts made of silver powder, but also minute non-sM parts made of vinyl chloride lacquer dotted in the silver powder. Because the tt part is formed, the conductivity as a whole is low.The electroforming material is electrodeposited in the minute non-conductive part made of vinyl chloride lacquer at the initial stage of electroforming. , which greatly contributes to the generation of minute non-electrodeposited areas.

By adjusting the degree of mixing of the vinyl chloride lacquer liquid in the spray liquid, the conductivity of the surface of the mandrel 5 can be freely set, and the size and distribution of the non-conductive parts can be changed. It is possible to change the dimensions and freely manage the number of through holes 2 per unit area of the mandrel 5 and the aperture ratio.

Moreover, other insulating materials may be used instead of the vinyl chloride lacquer solution as the mixed liquid in the spray solution.

Note that a silver plating film may be provided on the surface of the mandrel 5 to impart conductivity before the racking step.

After the racking process is finished, the mandrel 5 is washed again with water to remove foreign matter from the surface, and the pretreatment of the mandrel 5 is completed.

(2) In this embodiment, the step of activating the surface of the mandrel 5 using a pretreatment liquid in the prior art is omitted. This is to facilitate the formation of minute non-electrodeposited portions on the surface of the mandrel 5 at the initial stage of electroforming.

(2) Subsequently, the mandrel 5 and the electroformed material 4 are immersed in the electrolytic solution 3 in the electrolytic solution tank A. At this time, the electrolytic solution 3 is in a stopped state without circulating, and the moving device 7 of the cathode rocker 6 is in an OFF state, so the mandrel 5 also does not move. This is to facilitate the generation of minute non-electrodeposited portions.

When the power supply S is turned on and a current of 3 A per area 100CN of the mandrel 5 is passed between the electroformed material 4 and the spray M8 of the mandrel 5, the electroformed material 4 is electrolyzed and sprayed onto the spray layer 8 of the mandrel 5. Coated and TI cast! ! 19 is formed.

At the beginning of this electroforming, as mentioned above, the spray 11
! 8, electroforming material 4 is used for the conductive part made of silver powder (electroforming material 4).
However, since the electroformed material 114 is difficult to MH in minute non-electroconductive areas formed by vinyl chloride lacquer scattered in the silver powder, minute non-electrodeposited areas are generated starting from these non-electroconductive areas.

As electroforming progresses, this minute non-fl! The seminal part grows and becomes a through hole 2.

In particular, in this embodiment, in addition to the presence of this non-corridor part, as described above, there are various adjustments such as adjusting the composition of the electrolytic solution 3, omitting the surface activation treatment of the mandrel 5, stopping the cathode rocker 6, and adjusting the current. The addition of technology makes the generation and growth of the non-C1i deposits easier.

In addition, in this embodiment, the through hole 2 becomes zero M as the NvI progresses.
IF! 9 grew not only in the thickness direction but also in the radial direction, and the diameter of the through hole 2 was enlarged on the viewing side of the mold body 1.

Then, the entire desired surface of the mandrel 5 is coated with the fft'* layer 9, and the electroformed W! After confirming that many through holes 2 have not been formed in J9, the current is reduced to about 1 to 2 A per 100 csλ of area of mandrel 5. Thereafter, by circulating the electrolytic solution 3 and further operating the cathode rocker 6, the cathode current density is made uniform, so that the thickness of the electroformed IF 19 becomes uniform.

(2) When the surface of the mandrel 5 is electroformed as described above, the mandrel 5 is taken out from the electrolytic solution 3 and dried. After this, the electroformed layer 9 is peeled off from the mandrel 5. Note that since the spray IF 18 is interposed between the electroformed m9 and the surface of the mandrel 5, the electroformed layer 9 can be easily peeled off. The electroformed material 1Pj9 removed from the mandrel 5 is used as the mold body 1 of the mold.

(Second example) Next, a second embodiment of the invention will be described.

In this example, surfactant additives such as sodium lauryl sulfate are not added to the electrolyte 3 as in the first example, but the other steps are different from the first example and are similar to normal electroforming. It is something that is done.

In this case, since the generation of pinholes on the surface of the mandrel 5 is promoted only by the modification of the electrolytic solution 3, the rate of occurrence of the through holes 2 is extremely low compared to the case of the first embodiment.

In addition to this electroforming method, we mixed vinyl chloride lacquer into the spray liquid and sprayed it in the pretreatment of mandrel 5!
If 1118 is formed, the incidence of through holes 2 can be slightly increased.

Furthermore, (1) In the pretreatment of the mandrel 5, no pretreatment liquid is used.

(2) During electroforming, the electrolytic solution 3 is not circulated, and the cathode rocker 6 is generally kept in a stopped state.

(3) Applying a stronger current than usual during electroforming.

By appropriately combining the following steps, the mold body 1
The number of through holes 2 can be managed.

Note that this invention is not limited to the above-described embodiments; for example, as the electroforming material 4, a metal that is electrolyzed with positive ions may be used instead of nickel, as long as it does not depart from the spirit of the invention. Any changes are possible.

Effects of the Invention As detailed above, the present invention has a mold body with a large number of through holes formed by growing the minute non-MIT portions generated at the initial stage of electroforming during the same electroforming process. By using it for molding, it has excellent effects such as easy degassing, less clogging of the through holes, and easy cleaning of the insides of the through holes.

[Brief explanation of the drawing]

11M is a cross-sectional view showing the usage state of the mold according to this example, FIG. 2(a) is a schematic diagram showing the electroforming method for manufacturing the mold, and FIG. FIG. 3(a) is a plan view, FIG. 3(a) is a sectional view showing a state in which the mandrel is electroformed, and FIG. 3(b) is a partially broken enlarged sectional view of the mold. Mold body 1, through hole 2, object to be molded W1 rim molding device D0 Patent applicant Konan Tokushu Sangyo Co., Ltd. Agent Patent attorney On 1) Hiroshi Nobuo drawing collection ID] Drawing 2

Claims (1)

[Claims] 1. A mold body (1) formed by electroforming, in which a minute non-electrodeposited part generated at the initial stage of electroforming is grown during the same electroforming process to form a mold body (1) between the front and back surfaces. Numerous through holes (
2) A method for forming a rim of a synthetic resin molded product, characterized in that rim forming is performed by injecting a reactive material (W) into a mold body (1) having: