CA1307087C - Process for producing a multilayer molded article - Google Patents
Process for producing a multilayer molded articleInfo
- Publication number
- CA1307087C CA1307087C CA000579807A CA579807A CA1307087C CA 1307087 C CA1307087 C CA 1307087C CA 000579807 A CA000579807 A CA 000579807A CA 579807 A CA579807 A CA 579807A CA 1307087 C CA1307087 C CA 1307087C
- Authority
- CA
- Canada
- Prior art keywords
- skin material
- mold
- resin melt
- resin
- molds
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
Abstract:
A process for producing a multilayer molded article comprises supplying at least one piece of a skin material having a desired shape and resin melt between unclosed upper and lower molds and closing the molds to form a multilayer molded article comprising the thermoplastic resin and the skin material, the latter covering only a desired part of the article. The resin melt is supplied at or near a center area of a rear face of the skin material. Or, after the skin material has been lifted to a position at which the skin material contacts a cavity surface of the upper mold, the resin melt is supplied between the upper and lower molds. The process economically produces a multilayer molded article in which the skin material covers only a part of the article without displacement of such skin material, and provides an article with good feel.
A process for producing a multilayer molded article comprises supplying at least one piece of a skin material having a desired shape and resin melt between unclosed upper and lower molds and closing the molds to form a multilayer molded article comprising the thermoplastic resin and the skin material, the latter covering only a desired part of the article. The resin melt is supplied at or near a center area of a rear face of the skin material. Or, after the skin material has been lifted to a position at which the skin material contacts a cavity surface of the upper mold, the resin melt is supplied between the upper and lower molds. The process economically produces a multilayer molded article in which the skin material covers only a part of the article without displacement of such skin material, and provides an article with good feel.
Description
13C)~7 Process for producing a multilayer molded article The present invention relates to a process for producing a multilayer molded article comprising a thermoplastic resin and a skin material. More particularly, it relates to a process for producing a multilayer molded article comprising a thermoplastic resin and a skin material that covers only a desired part of the article.
Such a multilayer molded article in which the skin material covers only a desired part o the article is used 1~ as a door trim or a rear trim of an automobile or the like. Such an article is hereinafter referred to as a "skin material, partially laminated article". A known process for producing such an article comprises molding the thermoplastic resin by, for example, injection molding 15 and laminating the skin material with a desired shape on the molded article with an adhesive or the like. A
process is also known that comprises making a part by laminating the skin material on a hard board and attaching said part to the molded article with small screws or the like. These processes require post-processing of the article, which is time consuming and increases the production cost of the article.
Such a multilayer molded article in which the skin material covers only a desired part o the article is used 1~ as a door trim or a rear trim of an automobile or the like. Such an article is hereinafter referred to as a "skin material, partially laminated article". A known process for producing such an article comprises molding the thermoplastic resin by, for example, injection molding 15 and laminating the skin material with a desired shape on the molded article with an adhesive or the like. A
process is also known that comprises making a part by laminating the skin material on a hard board and attaching said part to the molded article with small screws or the like. These processes require post-processing of the article, which is time consuming and increases the production cost of the article.
- 2 - ~3~7~87 Japanese Patent Publication No. 28704/1981 and Japanese Patent Kokai Publication No. 177332/1983 disclose processes for integrally producing a skin material, partially laminated article by injection molding, which S comprise fixing the skin material at a desired position on an inner wall of a mold with a fastener or a magic band, closing the mold and then injecting the thermoplastic resin. These processes require special means for fixing the skin material to the mold. Further, since the resin melt is supplied after closing the mold and it flows at a very high flow rate in the very narrow clearance that corresponds to the difference between the thickness of the article and the thickness of the skin material, the rear face of the skin material receives a large shear force so that the skin material tends to be displaced even though a fastener or magic band is used. In addition, the skin material is largely influenced by heat, and, after the supply of the resin melt, a large pressure is applied to the skin material in a dwell time so that the grain pattern, texture, hand or feel (hereinafter referred to as the "feel") of the skin material tend to be impaired.
As a result of an extensive study of a process for producing a skin material, partially laminated article having a good feel without displacement of the skin material, it has been found that the conditions for supplying the resin melt are important.
In one aspect, the invention consists of a process for producing a multilayer molded article comprising supplying at least one piece of a skin material and a resin melt between unclosed upper and lower molds and closing the molds to form the multilayer molded article of the thermo-plastic resin with the skin material covering only a part of the article, wherein skin material of a desired shape is placed at a predetermined location on the lower mold and resin melt is supplied at or near a center area of a rear face of the skin material.
~7~8~7 In another aspect, the invention consists of a process for producing a multilayer molded article comprising supplying a piece of skin material and resin melt between unclosed upper and lower molds and closing the molds to form the multilayer molded article of the thermoplastic resin and the skin material, wherein a vertically movable rod or bar is provided at a part of the lower mold on which the skin material is positioned, and, after lifting the skin material by the rod or bar to a position at which at least a part of the skin material contacts a cavity surface of the upper mold, the resin melt is supplied between the skin material and the lower mold, the rod or bar being returned to a determined position before the molding is completed.
The process of the present invention will be illustrated by making reference to the accompanying drawings.
Fig. 1 shows a perspective view of a molded article produced by a process according to an embodiment of the present invention;
Fig. 2 shows a cross sectional view of the article of Fig. 1 alony the line A-A'; and Figs. 3 to 14 respectively show vertical cross sectional views of apparatus at different stages in the process-In Figs. 1 ~ 2, numeral 1 shows a multilayer moldedarticle, 2 shows a thermoplastic resin and 3 shows a skin material. In Figs. 3 to 14, 6 and 8 are upper and lower platens of a rnold closing machine, respectively, and 7 and 3~ 9 are upper and lower molds, respectively.
On a cavity surface of the lower mold 9, a shallow depression 10 is provided for determining the position in which the skin material 3 is placed.
By using such apparatus, the process is carried out according to the following four steps:
. . .
~7~7 l. The skin material 3 which has been cut to a desired size is placed with its outer surface down in a depression 10 of the lower mold 9.
2. A lifting mechanism (not shown) of the mold closing machine is actuated to lift the lower mold 9, and then the lower mold 9 is temporarily stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 is larger than the thickness of the article to be molded. At this position, resin melt 4 (Fig. 3) is supplied at or near the center area of the rear face of the skin material 3 through a resin passage (not shown) provided in the upper mold 7 by means of a conventional resin melt supplier (not shown) such as an extruder.
3. Thereafter, as shown in Fig. 4, the lifting mechanism is reactuated to further lift the lower mold 9 to press the skin material 3 against the lower mold 9 and spread the resin melt 4 in the mold cavity, whereby the skin material 3 and the thermoplastic resin 2 are 2() integrated and the molding is completed (Fig. 4).
4. After cooling the mold, the lower mold 9 is lowered to open the molds, and the molded article l is removed from the mold.
In this process the timing for supplying the resin melt 4 is not limited to the above described timing, and the resin melt can be supplied at any time after the skin material has been placed on the lower mold 9 and before the upper and lower molds are closed to their final position. In other words, besides the above timing sequence in which the mold is stopped at an intermediate position, the resin melt can be supplied before the mold closing is started, or during a continuously closing of the mold without stopping, if desired, with a decreased mold closing rate.
.~
i ~3~7~
Preferably, the resin melt 4 is supplied when the mold closing action is temporarily stopped after starting of the mold closing, or the mold closing rate is decreased to 30 mm/sec. or less, and the cavity clearance between the upper and lower molds 7 and 9 is not larger than (C + 100) mm and not smaller than (C + 5) mm wherein "C" represents the cavity clearance when the molding is completed. In this way, the feel of the skin material is maintained.
When the resin melt 4 is supplied through two or more passages, it is necessary to prevent confluence of the resin melt 4 from the passages on the skin material by adjusting the amount of resin melt supplied from each passage based on the size and other properties of the skin material 3, whereby to prevent penetration of the resin melt between the skin material 3 and the lower mold 9.
Since the resin melt 4 is supplied at or near the center area of the rear face of the skin material when the clearance between the upper and lower molds is still large, the resin melt 4 flows over the skin material 3 with a small shear force and spreads from the center area towards the periphery of the skin material. Therefore, the skin material 3 is unlikely to be moved out of position.
During the supply of the resin melt 4, a larger clearance between the upper and lower molds is preEerred to decrease the shear rate when the resin melt 4 flows over the skin material 3. However, if the clearance is too large, the shape of the supplied resin melt is deformed and therefore the resin melt 4 is ununiformly spread, which can cause movement of the skin material.
Further, it takes longer from the supply of the resin melt until the closing of the mold, so that the center area of the skin material 3 is heated for a longer period of time than the other parts and the feel of the skin material 3 tends to be deteriorated. In addition, the surface - 6 - ~3~7~87 condition of the part of the article on which no skin material is laminated tends to be deteriorated. Thus, the clearance of the mold is adjusted to a suitable value based on the kinds of material, the shape of the molded article, etc.
The present invention further provides a process that comprises placing the skin material 3 with its outer surface facing up on the cavity surface of the lower mold 9, and supplying the resin melt 4 at or near the rear face 10 of the skin material 3 through a passage (not shown) provided in the lower mold 9.
The skin material 3 is lifted by the resin melt 4 away from the lower mold 9 and is pressed against a predetermined part of the upper mold 8. In such a case, if the supply balance of the resin melt is not adequate, the skin material tends to be displaced. Therefore, in this process the clearance between the upper and lower molds during the supply of the resin melt is set to be less than in the former process in which the resin melt is 20 supplied from passages provided in the upper mold 7.
Instead of supplying the resin melt 4 from one or more passages in the mold, it can be supplied from a resin passage that is inserted into and removed from the clearance between the upper and lower molds. However, 25 this method is used only in a very limited case, since it is difficult to adjust the clearance of the mold during such a resin supply.
Since the skin material is not likely to be displaced, as explained above, means for preventing displacement of 3~ the skin material need not necessarily be used. However, it is still preferred to use such means in order to be sure to precisely position the skin material.
As such a displacement preventing means, the various means shown in Fig. 5 can be used. For example, as shown 35 in Fig. 5A, the depth of the depression lO is made substantially the same as the thickness of the skin 7- ~L307~87 material; as shown in Fig. 5B, a low wall 11 surrounding the skin material 3 is provided; as shown in Fig. 5C, a part of the mold on which the skin material is positioned is modified to form a telescopic element 13 that is pressed against the resin supply side by means of an expansion element 14, such as a spring, a hydraulic cylinder, a pneumatic cylinder or the like during the supply of the resin melt, and is returned to its original position as the supply of the resin melt 4 proceeds; or, in a case where the skin material 3 is of the fabric type, the part of the mold on which the skin material is placed is provided with some roughness 12, as shown in Fig. 5D.
In the case of Fig. 5D, not only is the displacement of the skin material prevented, but also the feel of the skin material is effectively maintained.
To supply the resin melt 4 at or near the center area of the skin material 3, the resin melt can be supplied from at least two inlets, the streams being integrated with each other to reach the center area of the skin material, or can be supplied from a single point near the center area.
When the position at which the skin material 3 is placed on the article deviates from the center of the article, in addition to the inlet provided near the center area of the rear face of the skin rnaterial, another inlet can be provided at a position for balancing the flows of resin melt. In this case, it is important that the flows o resin melts 4,5 (Fig. 7) do not meet each other on the skin material 3.
A laminated molded article can be produced by lifting the skin material 3 by a vertically movable rod 16 or bar 17 (Figs. 12 and 13) provided in the lower mold 9 up to a position at which at least a part of the skin material 3 contacts the surface of the upper mold, thereafter supplying the resin melt 4 between the skin material 3 and ~ - 8 - ~ ~7~87 the lower mold 9 and returning the rod 16 or the bar 17 to its original position at least before the molding is complete. By this method, since the skin material 3 is held by the rod 16 or the bar 17, it is unlikely to be S displaced and therefore the resin melt 4 need not necessarily be supplied at the center area of the rear face of the skin material.
The timing when the rod 16 or the bar 17 is returned to its original position can be any time after the start of the resin melt supply and before completion o~
molding. When a plurality of rods 16 and bars 17 are used, it is not necessary to return all of them to their original positions at the same time.
It is possible to use a mold that has a small wall 11 (Figs. 9 & 10) at a position on the lower mold 9 or the upper mold 7 corresponding to a boundary where the skin material 3 covers the thermoplastic resin 2 and a groove 15 which corresponds to the wall 11 on the other mold. In a multilayer molded article produced by using such a mold, 2~ an edge portion of the adhered skin material is buried in the article so that the boundary between one part of the article that is covered by the skin material and an adjacent part that is not, becomes distinct, and the finish of the article is improved. The skin material is resistant to peeling off at its edge.
Examples of skin material to be used are fabrics, non-woven fabrics, metals, nets of thermoplastic resins, paper, metal foils and sheets or films of thermoplastic resins and thermoplastic elastomers. The skin material 3~ can be decorated by a rugged pattern such as embossing, printing or dyeing, or in the form of a foam.
The skin material can be a laminated one consisting of at least two materials bonded together by, for example, an adhesive. In use, the skin material can be preheated, for example, to improve the adhesivity between the skin material and the resin.
~3~7~87 As the resin to be used, any one of the resins that are conventionally used in press molding, injection molding and extrusion molding can be used. Specific examples of resins are non-expandable or expandable resins of thermoplastic resins (e.g. polypropylene, polyethylene, polystyrene, acrylonitrile-styrene-butadiene block copolymers, nylon, etc.) and thermoplastic elastomers (e.g. ethylene-propylene block copolymers, styrene-butadiene block copolymers, etc.). The resin can contain a filler (e.g. inorganic fillers and glass fibers, etc.), pigments, lubricants, antistatic agents or the like.
The present invention will be further illustrated by the following Examples:
Example 1 By using molding equipment in which the upper mold 7 had a passage and an inlet for supplying the resin melt 4, a multilayer molded article was produced by the following steps i) to iv):
i) Two pieces of a skin material cut to desired sizes 2~ (a composite material made of an embossing sheet of polyvinyl chloride having a thickness of 0.6 mm and a sheet of polypropylene foam having a thickness of 3 mm and an expansion ratio of 15) were placed with their surfaces down on the depressions 10 of the lower mold 9.
ii) The lifting mechanism of the mold closing machine was actuated to lift the lower mold 9, and then the lower mold 9 was stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 was 30 mm. At that position, resin melt kept at 3~ 200C (Sumitomo Noblen (registered trade mark) AZ 56~, polypropylene manufactured by Sumitomo Chemical Company Limited) was supplied at or near the center area of the rear face of each piece of skin material 3 through the resin passage in the upper mold 7 (Fig. 3).
-- 1 o - ~3~7~87 iii) Thereafter, the lifting mechanism was reactuated to further lift the lower mold 9 at a rate of 10 mm/sec.
to press the skin material 3 against the lower mold 9.
The resin melt 4 was thereby spread in the mold cavity, whereby the skin material 3 and the thermoplastic resin 2 were integrated and the molding was completed (Fig. 4).
iv) After cooling the mold, the lower mold 9 was lowered to open the molds, and the molded article 1 having a thickness of 3 mm was removed from the mold.
The produced article 1 had no displacement of the skin material and a good feel.
Example 2 By using molding equipment in which the lower mold 9 had passages and inlets for supplying resin melt 4,5, a multilayer molded article 1 was produced by the following steps i) to iv):
i) Two pieces of a skin material 3 cut to desired sizes (a non-woven fabric of polyester having an average weight (METSUKE) of 300 g/m2) were placed with their surfaces up on the depressions 10 of the lower mold 9.
ii) The lifting mechanism of the mold closing machine was actuated to lower the upper mold 7, and then the upper mold 7 was stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 was 10 mm (Fig. 6). At that position, resin melt kept at 200C (Sumitomo Noblen (registered trade mark) AZ 564, polypropylene manufactured by Sumitotno Chemical Company Limited) was supplied at or near the center area of the rear face of each piece of skin material 3 through the resin passage in the lower mold 9. To balance the resin melt flow, another portion of the resin melt 5 was supplied from the other inlet. Each skin material 3 was lifted by the resin melt 4 from the lower mold 9 and pressed against the respective predetermined part of the upper mold 7 having roughness 12.
, ~
3~7~87 iii) Thereafter, the lifting mechanism was reactuated to further lower the upper mold 7 at a rate of 20 mm/sec.
so as to spread the resin melt 4,5 in the mold cavity while pressing the skin material, whereby the skin material 3 and the thermoplastic resin 2 were integrated and the molding was completed (Fig. 8).
iv) After cooling the mold, the upper mold 7 was lifted to open the molds, and the molded article having a thickness of 3 mm was removed from the mold.
The produced article l had no displacement of the skin material and a good feel.
Comparative Example l Under the same conditions as in Example 2 but supplying the resin melt 4 at an edge part of the rear face of the skin material from a passage provided in the lower mold 9, a multilayer molded article was produced.
The skin material was found to be displaced from the intended position in the produced article.
Comparative Example 2 2~ Under the same conditions as in Example 2 but injection supplying the resin melt by applying a predetermined clamrod force after closing the upper and lower molds 7,9 to the finally closed position (conventional injection molding), a multilayer molded 2S article was produced.
Although the produced article had no displacement of the skin material, the resin penetrated into the skin material 3 so that the article had a very poor feel.
Example 3 Under the same conditions as in Example 2 but using a mold in which a small wall ll was provided on the cavity surface of the upper mold 7 at a position corresponding to a boundary where the skin material 3 covers the thermoplastic resin 2, with a groove 15 on the cavity surface of the lower mold 9 at a position corresponding to - 12 ~ ~3~7~87 the small wall, a multilayer molded article was produced (Figs. 9-11).
In the produced article, the boundaries between the part covered with the skin material and the adjacent parts not so covered were clear and the feel was good.
Example 4 By using molding equipment comprising a mold in which a small wall 11 was provided on the cavity surface of the upper mold 7 at a position corresponding to a boundary where the skin material 3 covers the thermoplastic resin 2, with a groove 15 provided on the cavity surface of the lower mold 9 at a position corresponding to the small wall, and with a vertically movable rod 16 and bar 17 and a passage and an inlet for supplying the resin melt 4 provided in the lower mold 9, a multilayer molded article was produced by the following steps i) to v):
i) A piece of a skin material 3 cut to a desired size (a composite material made of an embossing sheet of polyvinyl chloride having a thickness of 0.6 mm and a 2~ fabric of woolly nylon having a thickness of 0.2 mm) was placed with its surface up along the groove 15 of the lower mold 9.
ii~ The lifting mechanism of the mold closing machine was actuated to lower the upper rnold 7, and then the upper mold 7 was stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 was 15 mm (Fig. 12). At that position, the rod 16 and the bar 17 were moved upwardly to lift the skin material 3 so that it just touched a predetermined part of the surface of the upper mold.
iii) Under such condition, resin melt kept at 240C
(Klarastic (registered trade mark) MTH-2, an ABS resin manufactured by Sumitomo Naugatuck Company Limited) was supplied at two areas of the surface of the skin material 3 through resin passages provided in the lower mold 9 (Fig. 13). After 0.5 and 1.0 seconds from the start of - 13 ~ ~3~7~87 resin supply, the pin 16 and the bar 17 were lowered to their original positions, respectively.
iv) Thereafter, the lifting mechanism was reactuated to further lower the upper mold at a rate of 15 mm/sec. so as to spread the resin melt in the mold cavity while pressing the skin material 3, whereby the skin material 3 and the thermoplastic resin 2 were integrated and the molding was complete (Fig. 14).
v) After cooling the mold, the upper mold 7 was lifted to open the molds, and the molded article 1 having a thickness of 3 mm was removed from the mold.
The produced article 1 had no displacement of skin material and a good feel.
.~
As a result of an extensive study of a process for producing a skin material, partially laminated article having a good feel without displacement of the skin material, it has been found that the conditions for supplying the resin melt are important.
In one aspect, the invention consists of a process for producing a multilayer molded article comprising supplying at least one piece of a skin material and a resin melt between unclosed upper and lower molds and closing the molds to form the multilayer molded article of the thermo-plastic resin with the skin material covering only a part of the article, wherein skin material of a desired shape is placed at a predetermined location on the lower mold and resin melt is supplied at or near a center area of a rear face of the skin material.
~7~8~7 In another aspect, the invention consists of a process for producing a multilayer molded article comprising supplying a piece of skin material and resin melt between unclosed upper and lower molds and closing the molds to form the multilayer molded article of the thermoplastic resin and the skin material, wherein a vertically movable rod or bar is provided at a part of the lower mold on which the skin material is positioned, and, after lifting the skin material by the rod or bar to a position at which at least a part of the skin material contacts a cavity surface of the upper mold, the resin melt is supplied between the skin material and the lower mold, the rod or bar being returned to a determined position before the molding is completed.
The process of the present invention will be illustrated by making reference to the accompanying drawings.
Fig. 1 shows a perspective view of a molded article produced by a process according to an embodiment of the present invention;
Fig. 2 shows a cross sectional view of the article of Fig. 1 alony the line A-A'; and Figs. 3 to 14 respectively show vertical cross sectional views of apparatus at different stages in the process-In Figs. 1 ~ 2, numeral 1 shows a multilayer moldedarticle, 2 shows a thermoplastic resin and 3 shows a skin material. In Figs. 3 to 14, 6 and 8 are upper and lower platens of a rnold closing machine, respectively, and 7 and 3~ 9 are upper and lower molds, respectively.
On a cavity surface of the lower mold 9, a shallow depression 10 is provided for determining the position in which the skin material 3 is placed.
By using such apparatus, the process is carried out according to the following four steps:
. . .
~7~7 l. The skin material 3 which has been cut to a desired size is placed with its outer surface down in a depression 10 of the lower mold 9.
2. A lifting mechanism (not shown) of the mold closing machine is actuated to lift the lower mold 9, and then the lower mold 9 is temporarily stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 is larger than the thickness of the article to be molded. At this position, resin melt 4 (Fig. 3) is supplied at or near the center area of the rear face of the skin material 3 through a resin passage (not shown) provided in the upper mold 7 by means of a conventional resin melt supplier (not shown) such as an extruder.
3. Thereafter, as shown in Fig. 4, the lifting mechanism is reactuated to further lift the lower mold 9 to press the skin material 3 against the lower mold 9 and spread the resin melt 4 in the mold cavity, whereby the skin material 3 and the thermoplastic resin 2 are 2() integrated and the molding is completed (Fig. 4).
4. After cooling the mold, the lower mold 9 is lowered to open the molds, and the molded article l is removed from the mold.
In this process the timing for supplying the resin melt 4 is not limited to the above described timing, and the resin melt can be supplied at any time after the skin material has been placed on the lower mold 9 and before the upper and lower molds are closed to their final position. In other words, besides the above timing sequence in which the mold is stopped at an intermediate position, the resin melt can be supplied before the mold closing is started, or during a continuously closing of the mold without stopping, if desired, with a decreased mold closing rate.
.~
i ~3~7~
Preferably, the resin melt 4 is supplied when the mold closing action is temporarily stopped after starting of the mold closing, or the mold closing rate is decreased to 30 mm/sec. or less, and the cavity clearance between the upper and lower molds 7 and 9 is not larger than (C + 100) mm and not smaller than (C + 5) mm wherein "C" represents the cavity clearance when the molding is completed. In this way, the feel of the skin material is maintained.
When the resin melt 4 is supplied through two or more passages, it is necessary to prevent confluence of the resin melt 4 from the passages on the skin material by adjusting the amount of resin melt supplied from each passage based on the size and other properties of the skin material 3, whereby to prevent penetration of the resin melt between the skin material 3 and the lower mold 9.
Since the resin melt 4 is supplied at or near the center area of the rear face of the skin material when the clearance between the upper and lower molds is still large, the resin melt 4 flows over the skin material 3 with a small shear force and spreads from the center area towards the periphery of the skin material. Therefore, the skin material 3 is unlikely to be moved out of position.
During the supply of the resin melt 4, a larger clearance between the upper and lower molds is preEerred to decrease the shear rate when the resin melt 4 flows over the skin material 3. However, if the clearance is too large, the shape of the supplied resin melt is deformed and therefore the resin melt 4 is ununiformly spread, which can cause movement of the skin material.
Further, it takes longer from the supply of the resin melt until the closing of the mold, so that the center area of the skin material 3 is heated for a longer period of time than the other parts and the feel of the skin material 3 tends to be deteriorated. In addition, the surface - 6 - ~3~7~87 condition of the part of the article on which no skin material is laminated tends to be deteriorated. Thus, the clearance of the mold is adjusted to a suitable value based on the kinds of material, the shape of the molded article, etc.
The present invention further provides a process that comprises placing the skin material 3 with its outer surface facing up on the cavity surface of the lower mold 9, and supplying the resin melt 4 at or near the rear face 10 of the skin material 3 through a passage (not shown) provided in the lower mold 9.
The skin material 3 is lifted by the resin melt 4 away from the lower mold 9 and is pressed against a predetermined part of the upper mold 8. In such a case, if the supply balance of the resin melt is not adequate, the skin material tends to be displaced. Therefore, in this process the clearance between the upper and lower molds during the supply of the resin melt is set to be less than in the former process in which the resin melt is 20 supplied from passages provided in the upper mold 7.
Instead of supplying the resin melt 4 from one or more passages in the mold, it can be supplied from a resin passage that is inserted into and removed from the clearance between the upper and lower molds. However, 25 this method is used only in a very limited case, since it is difficult to adjust the clearance of the mold during such a resin supply.
Since the skin material is not likely to be displaced, as explained above, means for preventing displacement of 3~ the skin material need not necessarily be used. However, it is still preferred to use such means in order to be sure to precisely position the skin material.
As such a displacement preventing means, the various means shown in Fig. 5 can be used. For example, as shown 35 in Fig. 5A, the depth of the depression lO is made substantially the same as the thickness of the skin 7- ~L307~87 material; as shown in Fig. 5B, a low wall 11 surrounding the skin material 3 is provided; as shown in Fig. 5C, a part of the mold on which the skin material is positioned is modified to form a telescopic element 13 that is pressed against the resin supply side by means of an expansion element 14, such as a spring, a hydraulic cylinder, a pneumatic cylinder or the like during the supply of the resin melt, and is returned to its original position as the supply of the resin melt 4 proceeds; or, in a case where the skin material 3 is of the fabric type, the part of the mold on which the skin material is placed is provided with some roughness 12, as shown in Fig. 5D.
In the case of Fig. 5D, not only is the displacement of the skin material prevented, but also the feel of the skin material is effectively maintained.
To supply the resin melt 4 at or near the center area of the skin material 3, the resin melt can be supplied from at least two inlets, the streams being integrated with each other to reach the center area of the skin material, or can be supplied from a single point near the center area.
When the position at which the skin material 3 is placed on the article deviates from the center of the article, in addition to the inlet provided near the center area of the rear face of the skin rnaterial, another inlet can be provided at a position for balancing the flows of resin melt. In this case, it is important that the flows o resin melts 4,5 (Fig. 7) do not meet each other on the skin material 3.
A laminated molded article can be produced by lifting the skin material 3 by a vertically movable rod 16 or bar 17 (Figs. 12 and 13) provided in the lower mold 9 up to a position at which at least a part of the skin material 3 contacts the surface of the upper mold, thereafter supplying the resin melt 4 between the skin material 3 and ~ - 8 - ~ ~7~87 the lower mold 9 and returning the rod 16 or the bar 17 to its original position at least before the molding is complete. By this method, since the skin material 3 is held by the rod 16 or the bar 17, it is unlikely to be S displaced and therefore the resin melt 4 need not necessarily be supplied at the center area of the rear face of the skin material.
The timing when the rod 16 or the bar 17 is returned to its original position can be any time after the start of the resin melt supply and before completion o~
molding. When a plurality of rods 16 and bars 17 are used, it is not necessary to return all of them to their original positions at the same time.
It is possible to use a mold that has a small wall 11 (Figs. 9 & 10) at a position on the lower mold 9 or the upper mold 7 corresponding to a boundary where the skin material 3 covers the thermoplastic resin 2 and a groove 15 which corresponds to the wall 11 on the other mold. In a multilayer molded article produced by using such a mold, 2~ an edge portion of the adhered skin material is buried in the article so that the boundary between one part of the article that is covered by the skin material and an adjacent part that is not, becomes distinct, and the finish of the article is improved. The skin material is resistant to peeling off at its edge.
Examples of skin material to be used are fabrics, non-woven fabrics, metals, nets of thermoplastic resins, paper, metal foils and sheets or films of thermoplastic resins and thermoplastic elastomers. The skin material 3~ can be decorated by a rugged pattern such as embossing, printing or dyeing, or in the form of a foam.
The skin material can be a laminated one consisting of at least two materials bonded together by, for example, an adhesive. In use, the skin material can be preheated, for example, to improve the adhesivity between the skin material and the resin.
~3~7~87 As the resin to be used, any one of the resins that are conventionally used in press molding, injection molding and extrusion molding can be used. Specific examples of resins are non-expandable or expandable resins of thermoplastic resins (e.g. polypropylene, polyethylene, polystyrene, acrylonitrile-styrene-butadiene block copolymers, nylon, etc.) and thermoplastic elastomers (e.g. ethylene-propylene block copolymers, styrene-butadiene block copolymers, etc.). The resin can contain a filler (e.g. inorganic fillers and glass fibers, etc.), pigments, lubricants, antistatic agents or the like.
The present invention will be further illustrated by the following Examples:
Example 1 By using molding equipment in which the upper mold 7 had a passage and an inlet for supplying the resin melt 4, a multilayer molded article was produced by the following steps i) to iv):
i) Two pieces of a skin material cut to desired sizes 2~ (a composite material made of an embossing sheet of polyvinyl chloride having a thickness of 0.6 mm and a sheet of polypropylene foam having a thickness of 3 mm and an expansion ratio of 15) were placed with their surfaces down on the depressions 10 of the lower mold 9.
ii) The lifting mechanism of the mold closing machine was actuated to lift the lower mold 9, and then the lower mold 9 was stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 was 30 mm. At that position, resin melt kept at 3~ 200C (Sumitomo Noblen (registered trade mark) AZ 56~, polypropylene manufactured by Sumitomo Chemical Company Limited) was supplied at or near the center area of the rear face of each piece of skin material 3 through the resin passage in the upper mold 7 (Fig. 3).
-- 1 o - ~3~7~87 iii) Thereafter, the lifting mechanism was reactuated to further lift the lower mold 9 at a rate of 10 mm/sec.
to press the skin material 3 against the lower mold 9.
The resin melt 4 was thereby spread in the mold cavity, whereby the skin material 3 and the thermoplastic resin 2 were integrated and the molding was completed (Fig. 4).
iv) After cooling the mold, the lower mold 9 was lowered to open the molds, and the molded article 1 having a thickness of 3 mm was removed from the mold.
The produced article 1 had no displacement of the skin material and a good feel.
Example 2 By using molding equipment in which the lower mold 9 had passages and inlets for supplying resin melt 4,5, a multilayer molded article 1 was produced by the following steps i) to iv):
i) Two pieces of a skin material 3 cut to desired sizes (a non-woven fabric of polyester having an average weight (METSUKE) of 300 g/m2) were placed with their surfaces up on the depressions 10 of the lower mold 9.
ii) The lifting mechanism of the mold closing machine was actuated to lower the upper mold 7, and then the upper mold 7 was stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 was 10 mm (Fig. 6). At that position, resin melt kept at 200C (Sumitomo Noblen (registered trade mark) AZ 564, polypropylene manufactured by Sumitotno Chemical Company Limited) was supplied at or near the center area of the rear face of each piece of skin material 3 through the resin passage in the lower mold 9. To balance the resin melt flow, another portion of the resin melt 5 was supplied from the other inlet. Each skin material 3 was lifted by the resin melt 4 from the lower mold 9 and pressed against the respective predetermined part of the upper mold 7 having roughness 12.
, ~
3~7~87 iii) Thereafter, the lifting mechanism was reactuated to further lower the upper mold 7 at a rate of 20 mm/sec.
so as to spread the resin melt 4,5 in the mold cavity while pressing the skin material, whereby the skin material 3 and the thermoplastic resin 2 were integrated and the molding was completed (Fig. 8).
iv) After cooling the mold, the upper mold 7 was lifted to open the molds, and the molded article having a thickness of 3 mm was removed from the mold.
The produced article l had no displacement of the skin material and a good feel.
Comparative Example l Under the same conditions as in Example 2 but supplying the resin melt 4 at an edge part of the rear face of the skin material from a passage provided in the lower mold 9, a multilayer molded article was produced.
The skin material was found to be displaced from the intended position in the produced article.
Comparative Example 2 2~ Under the same conditions as in Example 2 but injection supplying the resin melt by applying a predetermined clamrod force after closing the upper and lower molds 7,9 to the finally closed position (conventional injection molding), a multilayer molded 2S article was produced.
Although the produced article had no displacement of the skin material, the resin penetrated into the skin material 3 so that the article had a very poor feel.
Example 3 Under the same conditions as in Example 2 but using a mold in which a small wall ll was provided on the cavity surface of the upper mold 7 at a position corresponding to a boundary where the skin material 3 covers the thermoplastic resin 2, with a groove 15 on the cavity surface of the lower mold 9 at a position corresponding to - 12 ~ ~3~7~87 the small wall, a multilayer molded article was produced (Figs. 9-11).
In the produced article, the boundaries between the part covered with the skin material and the adjacent parts not so covered were clear and the feel was good.
Example 4 By using molding equipment comprising a mold in which a small wall 11 was provided on the cavity surface of the upper mold 7 at a position corresponding to a boundary where the skin material 3 covers the thermoplastic resin 2, with a groove 15 provided on the cavity surface of the lower mold 9 at a position corresponding to the small wall, and with a vertically movable rod 16 and bar 17 and a passage and an inlet for supplying the resin melt 4 provided in the lower mold 9, a multilayer molded article was produced by the following steps i) to v):
i) A piece of a skin material 3 cut to a desired size (a composite material made of an embossing sheet of polyvinyl chloride having a thickness of 0.6 mm and a 2~ fabric of woolly nylon having a thickness of 0.2 mm) was placed with its surface up along the groove 15 of the lower mold 9.
ii~ The lifting mechanism of the mold closing machine was actuated to lower the upper rnold 7, and then the upper mold 7 was stopped at a position where the clearance between the cavity surfaces of the upper and lower molds 7 and 9 was 15 mm (Fig. 12). At that position, the rod 16 and the bar 17 were moved upwardly to lift the skin material 3 so that it just touched a predetermined part of the surface of the upper mold.
iii) Under such condition, resin melt kept at 240C
(Klarastic (registered trade mark) MTH-2, an ABS resin manufactured by Sumitomo Naugatuck Company Limited) was supplied at two areas of the surface of the skin material 3 through resin passages provided in the lower mold 9 (Fig. 13). After 0.5 and 1.0 seconds from the start of - 13 ~ ~3~7~87 resin supply, the pin 16 and the bar 17 were lowered to their original positions, respectively.
iv) Thereafter, the lifting mechanism was reactuated to further lower the upper mold at a rate of 15 mm/sec. so as to spread the resin melt in the mold cavity while pressing the skin material 3, whereby the skin material 3 and the thermoplastic resin 2 were integrated and the molding was complete (Fig. 14).
v) After cooling the mold, the upper mold 7 was lifted to open the molds, and the molded article 1 having a thickness of 3 mm was removed from the mold.
The produced article 1 had no displacement of skin material and a good feel.
.~
Claims (11)
1. A process for producing a multilayer molded article which comprises:
supplying at least one piece of a skin material and then a resin melt between unclosed upper and lower molds, wherein the resin melt is supplied after temporarily stopping the closing of the molds or decreasing the mold closing rate to 30 mm/sec. or less, and wherein a cavity clearance between the upper and lower molds is not larger than (C + 100)mm and not smaller than (C + 5)mm wherein C represents cavity clearance between the molds when the molding process is completed; and then closing the molds to spread the resin melt and form the multilayer molded article comprising a resin and the skin material which covers only a part of the surface of the article, wherein the skin material is placed at a predetermined skin material position on one of the lower or upper molds to prevent displacement of the skin material due to spreading the resin melt, and the resin melt is supplied at or near a center area of an outward face of the skin material, wherein said predetermined position is a structure selected from the group consisting of a depression in the mold, a boundary wall on the mold, a telescopic element in the mold and an uneven surface area in the mold.
supplying at least one piece of a skin material and then a resin melt between unclosed upper and lower molds, wherein the resin melt is supplied after temporarily stopping the closing of the molds or decreasing the mold closing rate to 30 mm/sec. or less, and wherein a cavity clearance between the upper and lower molds is not larger than (C + 100)mm and not smaller than (C + 5)mm wherein C represents cavity clearance between the molds when the molding process is completed; and then closing the molds to spread the resin melt and form the multilayer molded article comprising a resin and the skin material which covers only a part of the surface of the article, wherein the skin material is placed at a predetermined skin material position on one of the lower or upper molds to prevent displacement of the skin material due to spreading the resin melt, and the resin melt is supplied at or near a center area of an outward face of the skin material, wherein said predetermined position is a structure selected from the group consisting of a depression in the mold, a boundary wall on the mold, a telescopic element in the mold and an uneven surface area in the mold.
2. A process for producing a multilayer molded article which comprises:
supplying a piece of skin material and then a resin melt between unclosed upper and lower molds, wherein the resin melt is supplied after temporarily stopping the closing of the molds or decreasing the mold closing rate to 30 mm/sec. or less, and wherein a cavity clearance between the upper and lower molds is not larger than (C + 100)mm and not smaller than (C + 5)mm wherein C represents cavity clearance between the molds when the molding process is completed; and then closing the molds to spread the resin melt and form the multilayer molded article comprising a resin and the skin material which partially covers the article surface, wherein a vertically movable rod or bar is provided at a part of the lower mold on which the skin material is positioned, and after lifting the skin material to a position at which at least a part of the skin material contacts a cavity surface of the upper mold by the rod or bar, supplying the resin melt between the skin material and the lower mold and returning the lower mold and the rod or bar to a determined position at least before the molding is completed to prevent displacement of the skin material due to spreading the resin melt.
supplying a piece of skin material and then a resin melt between unclosed upper and lower molds, wherein the resin melt is supplied after temporarily stopping the closing of the molds or decreasing the mold closing rate to 30 mm/sec. or less, and wherein a cavity clearance between the upper and lower molds is not larger than (C + 100)mm and not smaller than (C + 5)mm wherein C represents cavity clearance between the molds when the molding process is completed; and then closing the molds to spread the resin melt and form the multilayer molded article comprising a resin and the skin material which partially covers the article surface, wherein a vertically movable rod or bar is provided at a part of the lower mold on which the skin material is positioned, and after lifting the skin material to a position at which at least a part of the skin material contacts a cavity surface of the upper mold by the rod or bar, supplying the resin melt between the skin material and the lower mold and returning the lower mold and the rod or bar to a determined position at least before the molding is completed to prevent displacement of the skin material due to spreading the resin melt.
3. The process according to claim 1, wherein the lower mold or the upper mold includes a boundary wall at the predetermined skin material position corresponding to a boundary where the skin material covers the resin and at least a groove which corresponds to the wall on the upper opposing mold.
4. The process according to claim 1, wherein the upper or lower mold includes a depression defined therein at the predetermined skin material position for positioning the skin material, said depression having a depth substantially the same as the thickness of the skin material.
5. The process according to claim 1, wherein the upper or lower mold includes a telescopic element at the predetermined skin material position for positioning the skin material thereon, said telescopic element being operatively connected to an expansion element for pressing the skin material against the resin melt.
6. The process according to claim 5, wherein said expansion element is a member selected from the group consisting of a spring, a hydraulic cylinder and a pneumatic cylinder.
7. The process according to claim 1, wherein the upper or lower mold includes an uneven surface area at the predetermined skin material position for positioning the skin material thereon and preventing displacement of the skin material during the process.
8. The process according to claim 1 or 2, wherein the skin material is selected from the group consisting of fabrics, non-woven fabrics, metals, nets of thermoplastic resins, paper, films of thermoplastic resins and films of thermoplastic elastomers.
9. The process according to claim 1 or 2, wherein the resin is a thermoplastic selected from the group consisting of polypropylene, polyethylene, polystyrene, acrylonitrile-styrene-butadiene block copolymers, and nylon.
10. The process according to claim 2, wherein the lower mold includes a boundary wall at the predetermined skin material position corresponding to a boundary where the skin material covers the resin and at least a groove which corresponds to the wall on the upper opposing mold.
11. The process according to claim 1 or 2, wherein the resin is an elastomer selected from a group consisting of ethylene-propylene block copolymers and styrene-butadiene block copolymers.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62218457A JPS6461213A (en) | 1987-08-31 | 1987-08-31 | Manufacture of laminated molding |
| JP62218458A JPS6461214A (en) | 1987-08-31 | 1987-08-31 | Manufacture of laminated moldings |
| EP88114132A EP0305969B1 (en) | 1987-08-31 | 1988-08-30 | Process for producing a multilayer molded article |
| CA000576091A CA1304552C (en) | 1987-08-31 | 1988-08-30 | Process for producing a multilayer molded article |
| DE88114132T DE3881794T2 (en) | 1987-08-31 | 1988-08-30 | Method of making a multi-layer molded article. |
| US07/238,857 US4873041A (en) | 1987-08-31 | 1988-08-31 | Process for producing a multilayer molded article |
| KR1019880011234A KR960015289B1 (en) | 1987-08-31 | 1988-08-31 | Process for producing a multilayer molded article |
| CA000579807A CA1307087C (en) | 1987-08-31 | 1988-10-11 | Process for producing a multilayer molded article |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62218458A JPS6461214A (en) | 1987-08-31 | 1987-08-31 | Manufacture of laminated moldings |
| CA000579807A CA1307087C (en) | 1987-08-31 | 1988-10-11 | Process for producing a multilayer molded article |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1307087C true CA1307087C (en) | 1992-09-08 |
Family
ID=25672169
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000579807A Expired - Lifetime CA1307087C (en) | 1987-08-31 | 1988-10-11 | Process for producing a multilayer molded article |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS6461214A (en) |
| CA (1) | CA1307087C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2508897B2 (en) * | 1990-07-13 | 1996-06-19 | 住友化学工業株式会社 | Laminated molded article and method for producing the same |
-
1987
- 1987-08-31 JP JP62218458A patent/JPS6461214A/en active Granted
-
1988
- 1988-10-11 CA CA000579807A patent/CA1307087C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0583054B2 (en) | 1993-11-24 |
| JPS6461214A (en) | 1989-03-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5053179A (en) | Process for producing a multilayer molded article | |
| CA1334613C (en) | Process for producing a multilayer molded article | |
| US5599608A (en) | Method of insert molding plastic parts to provide covered edge surfaces and plastic parts made thereby | |
| US5759464A (en) | Methods for manufacturing multilayer moldings | |
| RU2291052C2 (en) | Shaped article and method of its making | |
| EP0553795B1 (en) | Multilayer molded article and method for producing the same | |
| CA2058098C (en) | Process for producing multilayer molded article | |
| CA2077791C (en) | Process for producing multilayer molded article | |
| EP0376263B1 (en) | Process and mold for producing a multilayer molded article | |
| US5223201A (en) | Method of manufacturing a laminated body | |
| CA2006675C (en) | Process and mold for producing a multilayer molded article | |
| KR20030015155A (en) | Method and apparatus for molding components with molded-in surface texture | |
| CA2098854A1 (en) | Manufacturing device and manufacturing method for multi-layer molded-product | |
| EP0466181B1 (en) | Method for producing molded article of thermoplastic resin | |
| EP0376264B1 (en) | Process and mold for producing a multilayer molded article | |
| US6183680B1 (en) | Process for producing multilayer molded article | |
| US5593631A (en) | Method for molding resin articles | |
| EP0509371B1 (en) | Process for producing multilayer molded article | |
| CA1307087C (en) | Process for producing a multilayer molded article | |
| CA2091041A1 (en) | Plastic heat set molding | |
| US6382949B1 (en) | Metal mold for producing a synthetic resin molded product in a compression-molding method | |
| CA1296152C (en) | Method of making a laminated body and a molding apparatus for the same | |
| JPH05116164A (en) | Manufacture of multi layered molding | |
| JP2000167842A (en) | Thermoplastic resin molded article molding die |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |