CA2070290A1 - Sheetlike composite molded article and process for producing the same - Google Patents
Sheetlike composite molded article and process for producing the sameInfo
- Publication number
- CA2070290A1 CA2070290A1 CA 2070290 CA2070290A CA2070290A1 CA 2070290 A1 CA2070290 A1 CA 2070290A1 CA 2070290 CA2070290 CA 2070290 CA 2070290 A CA2070290 A CA 2070290A CA 2070290 A1 CA2070290 A1 CA 2070290A1
- Authority
- CA
- Canada
- Prior art keywords
- molded article
- molding
- primary
- mainly composed
- composite
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/16—Making multilayered or multicoloured articles
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Abstract A process for producing a composite molded article, comprising subjecting a resin material mainly composed of a flexible thermoplastic polyester elastomer as a secondary molding material to composite molding by double molding or two-color molding on a base molded article mainly composed of a rigid thermoplastic polyester as a primary molded article, thereby producing a composite molded article in sheet form or having a sheetlike part, characterized in that both surfaces of the sheetlike part in the primary molded article are subjected to secondary molding in such a manner that the sheetlike part is substantially symmetrically fusion-coated in its both surfaces with the secondary material or sandwiched in between the secondary material layers. The composite molded article is less susceptible to warpage and having a flexing resistance as a whole and a flexible sheetlike part on its surface.
Description
~- 207V29~
DESCRIPTION
SHEETLIKE COMPOSITE MOLDED ARTICLE AND PROCESS
FOR PRODUCING THE SAME
[Field of Industrial Application]
The present invention provides a molded article in the form of a flat or curved sheet or having a sheetlike part, said molded article being a composite molded article comprising two polyester resin materials and less susceptible to flexing as a whole, having a flexible surface and less susceptible to warpage, etc., during molding, and relates to a composite molded article suitable for use as various articles, such as articles whexe the softness to the touch is required and articles where impact or vibration absorption is required, the parts of equipment and tools, and a process for producing the same.
[Prior Art]
Sheetiike molded articles which should have a deflection resistance as a whole, be less susceptible to bending and have a flexible surface, or molded articles having a sheetlike part of the type described above have found many applications. In the articles molded from one and the same resin material, for example, an article molded from a material having a : , , - .
~ ` `'''' :
high rigidity, the surface has no flexibllity, while an article molded from a flexible material is soft as a whole and easily flexes due to poor deflection, so that the above-described requirement cannot be satisfied. For this reason, the current situation is that in order to obtain a molded article less susceptible to flexing derived from its deflection resistance as a whole and having flexibility in only its surface part, it is necessary to combine a hard material having a high rigidity with a soft material having flexibility.
A method generally adopted and widely known in the art for obtaining a molded article comprising the two materials of the type described above is the so-called insert (or outsert) molding method wherein a flexible resin material is provided by molding on a primary molded article mainly composed of a metallic material. The molded article produced by this method is heavy due to the use of a metal, is susceptible to peeling due to insufficient bonding of the boundary between both materials and is further unfavorably susceptible to corrosion, which limits the applications of the molded article. In order to reduce the weight, it is possible to employ the so-called double molding or two-color molding 20702~
(hereinafter generically referred to as the "double molding, etc.") which comprises molding a base through the use of a rigid resin material as a primary molded article and forming a surface layer through the use of a flexible resin material as a secondary material. In this case as well, since two different materials are generally used, the joint is liable to peel. In order to flrmly fuse the two materials to each other, it is necessary to employ such a troublesome procedure that an adhesive is applied to the primary molded article prior to the secondary molding.
The present inventors have made intensive studies on the selection of the combination of the materials and the configuration, structure, etc., with a view to producing a composite molded article in sheet form or having a sheetlike part less susceptible to deformation, such as flexing, and having a flexible surface and further free from the above-described problems, i.e., capabIe of equally maintaining various properties in respect of a reduction in the weight, fusing force (peeling strength between resins), appearance of molded article, mechanical properties, heat resistance, chemical properties, etc., particularly having an accurate configuration free from warpage during molding, which has led to the 20702~0 completion of the present invention.
[Disclosure of the Invention]
Accordingly, the present invention relates to a process for producing a composite molded article less susceptible to warpage and having a flexing resistance as a whole and a flexible sheetlike part on its surface, comprising subjecting a resin material mainly composed of a flexible thermoplastic polyester elastomer as a secondary molding material to composite molding by double molding or two-color molding on a base molded article mainly composed of a rigid thermoplastic polyester as a primary molded article, thereby producing a composite molded article in sheet form ~r having a sheetlike part, characterized in that both surfaces of the sheetlike part in the primary molded article are subjected to secondary molding in such a manner that the sheetlike part is substantially symmetrically fusion-coated in its both surfaces with or sandwiched by the secondary material, and a composite article molded by said process.
The composite molded article of the present invention is a molded article in sheet form or comprising a combination of sheetlike parts, for example, molded articles in box form or having an L-shaped, H-shaped or arciform cross section, or ,~ .
20702~
molded articles having a sheetlike part, for example, a flange part of a bobbin or a flange, and the sheetlike part may be in the form of not only a flat sheet but also a curved sheet (hereinafter generically referred to as the "sheetlike molded article").
The sheetlike composite molded article of the present lnvention is produced by composite molding according to the double molding, etc., through the use o~ a resin material mainly composed of a rigid thermoplastic polyester as a primary material (base molded artlcle) and a resin material mainly composed of a flexible thermoplastic polyester elastomer as the secondary material provided on the surface of the primary material, and characterized by the use of two particular polyester resin materials of the type described above in combination.
As described above, a composite molded article produced by the double molding, etc., through the use of a rigid thermoplastic resin as a primary molded article and a flexible thermoplastic resin as a secondary material is generally unsatisfactory in the strength of fusion between both the resins and in this case it is difficult to produce a composite molded article capable of equally satisfying various properties requirement in respect of the appearance and other properties such as mechanical, heat and chemical properties. However, it ls possible to produce a composite molded article capable of satisfyin~ the requirement for the above-described various properties through the use of a combination of particular resin materials, that is, the use of a resin material mainly composed of a rigid thermoplastic polyester as the primary molded article and a resin material mainly composed of a flexible thermoplastic polyester elastomer as the secondary material provided on the primary molded article. (A
description will be given later on both the resin materials).
As described above, however, even when use is made of a combination of the above-described particular resins, in the sheetlike molded article, mere composite molding of the secondary material on the flexible surface part alone in the molded article is liable to bring about warpage during the secondary 2~ molding, for example, brings about a problem of the accuracy of the configuration of the final molded article, such as a problem that no truly flat surface can be obtained in the case of a flat molded article.
In order to solve this problem, the present inventors have made further studies on the configuration and ': , 2~7~2~
structure of the secondary material in the formation of the sheetlike composite molded article and, as a result, have succeeded in significantly preventing the occurrence of warpage during the secondary molding through the composite molding of both surfaces of a rigid primary molded sheet as a base in such a manner that the sheetlike part is substantially symmetrically fusion-coated on its both surfaces with or sandwiched by a resin material mainly composed of a flexible thermoplastic polyester elastomer as a secondary material. The second feature of the present invention resides in this point. Specifically, in the composite molded article of the present invention, a flexible polyester elastomer resin material is provided not only on a surface having flexibility but also on the reverse surface so as to form a composite materlal wherein the two layers are symmetrically provided about the primary molded sheet. More specifically, in the double molding, etc., this is attained by previously providing a through-hole at a suitable position of the primary molded article or providing a notch at a part of the primary molded article and conducting secondary molding with the primary molded article supported by means of a mold for secondary molding in such a manner that the resin stream of the , ` ~ ;
,' :
secondary material reaches simultaneously both surfaces of the primary molded sheet. In this case, it is not always necessary to cover the whole of both the surfaces of the sheet as the primary molded article with the secondary material, and a surface necessary to have a partlcularly soft part from the viewpoint of design together with the reverse surface at a part substantially corresponding to the above part may be coated with the secondary material, or the secondary material may be provided so as to sandwich the above-described parts of the primary molded sheet.
In this case, both the surfaces of the primary molded sheet need not be always composite-coated similarly to each other. However, from the viewpoint of preventing the warpage, it is desired that both surfaces at respective positions which are symmetrical as much as possible be composited with the secondary material so that both the secondary material layers have substantially the same thickness with each other.
When the secondary material in both the surfaces is in a remarkably unbalanced state in respect of the position, area, thickness, etc., the effect of preventlng the warpage is reduced.
A description will now be given on the primary material and the secondary material. The resin material used as the primary material may be any one as far as it is a resin material mainly composed of a rigid thermoplastlc polyester resin. Fundamentally, however, since the composite molded article of the present invention, as such, should have deflection resistance and be less susceptible to flexing, the polyester resin should have an elastic modulus in bending of 15Q00 kgf/cm2 or more, preferably 20000 kgf/cm2 or more.
Specific examples thereof include polyalkylene terephthalates (with the number of carbon atoms in the alkylene group of 2 to 4) including polybutylene terephthalate and polyethylene terephthalate, known copolymers mainly composed of the polyalkylene terephthalates, and these resin materials blended with a minor amount of other thermoplastic resin as an auxiliary additive.
The primary resin material should be fused by the secondary material in the secondary molding.
Therefore, when the melting point is very high, it becomes necessary to raise the resin temperature of the secondary material in the secondary molding above that temperature. This is liable to bring about thermal decomposition and a remarkable lowering in the viscosity, so that there occurs a problem on the 2~7~29~
molding. For this reason, it is preferred to select a material having a melting point of 230C or below as the primary material. The melting point is particularly preferably 220C or below.
In view of the above, polybutylene terephthalate or a copolymer or a mixture mainly composed of polybutylene terephthalate is preferred as the primary material. There is no particular limitation on the kind of the comonomer, and any known comonomer may be ; 10 used. In general, the amount of incorporation of the comonomer is preferably 40% or less from the viewpoint of the ri.gidity.
In many cases, an inorganic filler is preferably incorporated in the primary material for the purpose of enhancing the mechanical properties and from the viewpoint of the heat resistance (heat deformation temperature), dimensional accuracy, etc., particularly from the viewpoint of increasing the deflection resistance of the final molded article~ Examples of the inorganic filler include fibrous reinforcements such as glass fibers and carbon fibers, glass flakes, glass powders, glass beads, mlca, calcium carbonate and other particulate and flaky fillers. However, the inorganic filler is not limited to these only, and any known inorganic filler may be selected for use in 20702~
imparting an intended property. Two or more inorganic fillers may be used in combination.
Other thermoplastic resin may be incorporated in a minor amount as an auxiliary additive in the primary material. The melting point, rigidity and other properties of the primary materlal may be regulated according to the purpose by the type of the thermoplastic polyester resin used, the type and amount of the comonomer, the type and amount of the thermoplastic resin used as other auxiliary additive and the type and amount of the inorganic filler.
The resin material for forming a flexible surface part of the sheetlike composite molded article according to the present invention is mainly composed of a thermoplastic polyester elastomer and in general the elastic modulus in bending thereof is preferably 10000 kg/cm2 or less from the viewpoint of imparting flexibility, still preferably 7000 kg/cm2 or less.
The polyester elastomer as the main ingredient constituting the secondary material may be any random or block copolyester comprising as the constituent a soft segment such as a polyoxyalkylene glycol ester, and any commercially available polyester elastomer or prepared polyester elastomer may be used.
Representative examples of the polyester 2~7029~
elastomer include a polyester copolymer comprislng a phthalate of polyoxyethylene glycol or polyoxybutylene glycol as the soft segment and butylene terephthalate or ethylene terephthalate as the other constituent.
The polyester elastomer may contain a minor amount of other thermoplastic resin as an auxiliary additive. The flexibility of the surface part of the composite molded article may be adjusted to an intended value through a proper selection of the content of the soft segment, for example, a polyoxyalkylene glycol ester segment, in the polyester elastomer, the molecular weight of the segment, other comonomer component, other auxiliary additive resin or the like.
The sheetlike composite molded article of the present invention is produced by subjecting the above-described rigid primary material to primary molding to form a sheet base molded article and subjecting a secondary material to molding and fusion according to the double molding, etc., so as to substantially symmetrically cover both surfaces of the base molded artlcle at its part which necessitates flexibility.
The resin temperature of the secondary material in the secondary molding should be above the melting point of the primary material, preferably 10 to 70C above the 207~29a melting point of the primary material from the viewpoint of attaining a high fusion.
In the sheetlike composite molded article of the present invention, the use of two particular selected polyester resin materials provides the followlng advantages:
(1) it is less susceptible to flexing as a whole even upon being exposed to a low external force by virtue of its high deflection resistance as a whole, (2) the surface is kept flexlble, (3) the base and the flexible part of the surface are flrmly fused to each other and are less liable to peel, (4) it ls excellent in the mechanical properties, heat resistance and chemical resistance as well, and (5) it is light in weight.
Further, in the secondary molding, since the sheet base molded article is coated on its both surfaces with the secondary material or sandwlched in between the secondary material layers, (6) the warpage is prevented during the molding, so that a sheetlike molded article having accurate dimension and configuration can be produced.
This renders the composite molded article of the , ?:
, ~07029~
present invention suitable for use in many applications where the above described properties are required.
[Brief Description of Drawings]
Fig. 1 is a diagram showing the configuration of a primary molded article used in Examples 1, 2 and 3;
Fig. 2 is a diagram showing the configurahion and structure of the composite molded article according to the present invention (Examples 1, 2 and 3);
Fig. 3 is a diagram showing a composite molded article outside the scope of the present invention (Comparative Examples 1, 2 and 3);
Fig. 4 is a diagram showing the configuration of a primary molded article used in Examples 4 and 5 according to the present invention;
Fig. 5 is a diagram showing the configuration and structure of the composite molded article according to the present invention (Examples 4 and 5); and Fig. 6 is a diagram showing another composite molded article outside the scope of the present invention (Comparative Examples 5 and 6). In the Figs. 1 to 6, (a) is a plan view, (b) is a cross-sectional view taken along line X-X of (a), and (c) is a bottom plan view.
1: primary molded article, 207029~
2: secondary molded article, 3: through hole of primary molded article, and 4: notch of secondary molded article.
[Examples]
The present invention will now be described in more detail with reference to the following Examples, though it is not limited to these only.
Examples 1 to 3 The following materials were used as a primary material and subjected to primary molding to produce boxes having a through hole at the center of the bottom sheet as shown in Fig. 1:
A-1: polybutylene terephthalate resin (melting point: 225C, modulus of elasticity in bending: 26000 kg/cm2), A-2: polybutylene terephthalate resin copolymer containing minor amount of polybutylene isophthalate (melting point: 205C, modulus of elasticity in bendlng: 26000 kg/cm2), A-3: composition comprising the polybutylene terephthalate copolymer resin A-2 and, incorporated therein, 20% of glass fiber and 20% of glass flake (modulus of elasticity in bending: about 90000 kg/cm2)O
Then, the boxy primary molded articles were mounted on 2~702~
a cavity of a mold for secondary molding conducted at a resin temperature of 250C through the use of the following material as a secondary material, thereby producing composite molded articles wherein both surfaces of the bottom sheet of the boxy primary molded article were melt-sandwiched in between the secondary material layers having a substantially equal thickness as shown in Fig. 2:
B-1: polyester elastomer (melting point: 182C, modulus of elasticity in bending: 720 kg/cm2) .
The properties such as the amount of warpage, appearance, flexing resistance and surface hardness after the secondary moldlng were evaluated.
Comparative Examples 1 to 4 Boxy primary molded articles shown in Fig. 1 were molded through the use of the same primary materials as those used in the Examples 1 to 3, i.e., A-1, A-2 and A-3, except that no through hole was provided at the center of the bottom sheet. The primary molded articles were mounted on a mold for secondary side molding and, as shown in Fig. 3, molded articles wherein only one surface was composited with a secondary material comprising the same thermoplastic polyester elastomer as that described in the B-1 were :, , ~ 17 -produced and subjected to the same evaluation as that described above (Comparative Examples 1, 2 and 3).
For comparison, a box having the same shape as that of the composite molded article shown in Fig. 2 was produced by single molding through the use of the secondary material (B-1) without the use of the primary material and evaluated (Comparative Example 4).
Regarding the evaluation method, the appearance was evaluated by judging the gloss, change of color, etc., of the surface of the secondary molded article with the naked eye.
The deflection resistance of the final molded article was evaluated by putting a boxy molded article upside down on a surface plate and touching with a finger to judge the deflection resistance of the bottom sheet by the touch.
The amount of recess (mm) of the center relative to both ends of the bottom sheet of the molded article was measured through the use of a three dimensional sizer, and this value was defined as the amount of warpage. The surface (secondary side) hardness was expressed by Shore hardness D.
The results are also given in Table 1.
~07029~
U~ _ _ _ __ ~' ~5~ o o o o o 'o o a)~ ~ ~r ~r ~r ~r ~r ~
~o ~ _ ~ . ~ _ C~a ~ ~ ~ a~
h ~1 ~1 S~ ~1 . ~ ~J
_ ~ ~
C ~ . . . . . .
O ~ ~ ra ~
~0~ _ _ _ U~ ~ ~ ~ ~ U7 ,~ 3- o _ o ___ o ~-1 ,C ,_ ~ ,~ ~ ~
~LI ~ ~ ~ ~0~ ~ ~ ~
m ~ i l I ~, m l ~s _ _ ~ m E ~ N r~) ~¢ ~f1 a ", _ _ ~1 N ~ ~ (~I ~r) ~r _ _ ~ .. _ X O O ~ O
~Z o1::1Z
Examples 4 and 5 Flat sheets having a notch as shown in Flg. 4 were molded through the use of the following materials as a primary material:
A-4: composition (modulus of elasticity in bending: about 32000 kg/cm2) comprising polybutylene terephthalate copolymer (melting point: 185C) and 5% of glass fiber, A-5: composition (modulus of elasticity in bending: about 80000 kg/cm2) comprising polybutylene terephthalate copolymer of the same type as that of A-4 and 20% of glass fiber and 20% of glass flake.
Then the molded articles were mounted on a mold for secondary side molding conducted at a secondary side resin temperature of 240C through the use of the following material as a secondary material, thereby producing composite molded articles wherein both surfaces of each molded article were substantially symmetrically melt-coated with the secondary material layers as shown in Fig. 5:
B-2: polyester elastomer (melting point: 198C, modulus of elasticity in bending: 1100 kg/cm2).
207~290 The evaluation was conducted in the same manner as that described above.
Comparative Examples 5 to 7 Boxy primary molded articles shown in Fig. 4 were molded through the use of the same primary materials as those used in the Examples 4 and 5, i.e., A-4 and A-5, except that no notch was provided. The primary molded articles were mounted on a mold for secondary molding and, as shown in Fig. 6, molded articles wherein or.ly one surface was composited with a secondary material comprising the same thermoplastic polyester elastomer as that described in the B-2 were produced and subjected to the same evaluation as that described above (Comparative Examples 5 and 6).
For comparison, a box having the same shape as that of the composite molded article shown in Fig. 5 was produced by single molding through the use of the secondary material ~B-2) without the use of the primary material and subjected to evaluation (Comparative Example 7).
The results are given in Table 2.
The composite molded article was curved by hand and the flexing resistance was evaluated by the touch.
, 2~7029~
a ~ _--~ 0~ ~
o ~ I ~ l I ~ l ~ ~ o ~1 ~
_ _ _ a x o ~ x o r~ z c~ ~ æ
DESCRIPTION
SHEETLIKE COMPOSITE MOLDED ARTICLE AND PROCESS
FOR PRODUCING THE SAME
[Field of Industrial Application]
The present invention provides a molded article in the form of a flat or curved sheet or having a sheetlike part, said molded article being a composite molded article comprising two polyester resin materials and less susceptible to flexing as a whole, having a flexible surface and less susceptible to warpage, etc., during molding, and relates to a composite molded article suitable for use as various articles, such as articles whexe the softness to the touch is required and articles where impact or vibration absorption is required, the parts of equipment and tools, and a process for producing the same.
[Prior Art]
Sheetiike molded articles which should have a deflection resistance as a whole, be less susceptible to bending and have a flexible surface, or molded articles having a sheetlike part of the type described above have found many applications. In the articles molded from one and the same resin material, for example, an article molded from a material having a : , , - .
~ ` `'''' :
high rigidity, the surface has no flexibllity, while an article molded from a flexible material is soft as a whole and easily flexes due to poor deflection, so that the above-described requirement cannot be satisfied. For this reason, the current situation is that in order to obtain a molded article less susceptible to flexing derived from its deflection resistance as a whole and having flexibility in only its surface part, it is necessary to combine a hard material having a high rigidity with a soft material having flexibility.
A method generally adopted and widely known in the art for obtaining a molded article comprising the two materials of the type described above is the so-called insert (or outsert) molding method wherein a flexible resin material is provided by molding on a primary molded article mainly composed of a metallic material. The molded article produced by this method is heavy due to the use of a metal, is susceptible to peeling due to insufficient bonding of the boundary between both materials and is further unfavorably susceptible to corrosion, which limits the applications of the molded article. In order to reduce the weight, it is possible to employ the so-called double molding or two-color molding 20702~
(hereinafter generically referred to as the "double molding, etc.") which comprises molding a base through the use of a rigid resin material as a primary molded article and forming a surface layer through the use of a flexible resin material as a secondary material. In this case as well, since two different materials are generally used, the joint is liable to peel. In order to flrmly fuse the two materials to each other, it is necessary to employ such a troublesome procedure that an adhesive is applied to the primary molded article prior to the secondary molding.
The present inventors have made intensive studies on the selection of the combination of the materials and the configuration, structure, etc., with a view to producing a composite molded article in sheet form or having a sheetlike part less susceptible to deformation, such as flexing, and having a flexible surface and further free from the above-described problems, i.e., capabIe of equally maintaining various properties in respect of a reduction in the weight, fusing force (peeling strength between resins), appearance of molded article, mechanical properties, heat resistance, chemical properties, etc., particularly having an accurate configuration free from warpage during molding, which has led to the 20702~0 completion of the present invention.
[Disclosure of the Invention]
Accordingly, the present invention relates to a process for producing a composite molded article less susceptible to warpage and having a flexing resistance as a whole and a flexible sheetlike part on its surface, comprising subjecting a resin material mainly composed of a flexible thermoplastic polyester elastomer as a secondary molding material to composite molding by double molding or two-color molding on a base molded article mainly composed of a rigid thermoplastic polyester as a primary molded article, thereby producing a composite molded article in sheet form ~r having a sheetlike part, characterized in that both surfaces of the sheetlike part in the primary molded article are subjected to secondary molding in such a manner that the sheetlike part is substantially symmetrically fusion-coated in its both surfaces with or sandwiched by the secondary material, and a composite article molded by said process.
The composite molded article of the present invention is a molded article in sheet form or comprising a combination of sheetlike parts, for example, molded articles in box form or having an L-shaped, H-shaped or arciform cross section, or ,~ .
20702~
molded articles having a sheetlike part, for example, a flange part of a bobbin or a flange, and the sheetlike part may be in the form of not only a flat sheet but also a curved sheet (hereinafter generically referred to as the "sheetlike molded article").
The sheetlike composite molded article of the present lnvention is produced by composite molding according to the double molding, etc., through the use o~ a resin material mainly composed of a rigid thermoplastic polyester as a primary material (base molded artlcle) and a resin material mainly composed of a flexible thermoplastic polyester elastomer as the secondary material provided on the surface of the primary material, and characterized by the use of two particular polyester resin materials of the type described above in combination.
As described above, a composite molded article produced by the double molding, etc., through the use of a rigid thermoplastic resin as a primary molded article and a flexible thermoplastic resin as a secondary material is generally unsatisfactory in the strength of fusion between both the resins and in this case it is difficult to produce a composite molded article capable of equally satisfying various properties requirement in respect of the appearance and other properties such as mechanical, heat and chemical properties. However, it ls possible to produce a composite molded article capable of satisfyin~ the requirement for the above-described various properties through the use of a combination of particular resin materials, that is, the use of a resin material mainly composed of a rigid thermoplastic polyester as the primary molded article and a resin material mainly composed of a flexible thermoplastic polyester elastomer as the secondary material provided on the primary molded article. (A
description will be given later on both the resin materials).
As described above, however, even when use is made of a combination of the above-described particular resins, in the sheetlike molded article, mere composite molding of the secondary material on the flexible surface part alone in the molded article is liable to bring about warpage during the secondary 2~ molding, for example, brings about a problem of the accuracy of the configuration of the final molded article, such as a problem that no truly flat surface can be obtained in the case of a flat molded article.
In order to solve this problem, the present inventors have made further studies on the configuration and ': , 2~7~2~
structure of the secondary material in the formation of the sheetlike composite molded article and, as a result, have succeeded in significantly preventing the occurrence of warpage during the secondary molding through the composite molding of both surfaces of a rigid primary molded sheet as a base in such a manner that the sheetlike part is substantially symmetrically fusion-coated on its both surfaces with or sandwiched by a resin material mainly composed of a flexible thermoplastic polyester elastomer as a secondary material. The second feature of the present invention resides in this point. Specifically, in the composite molded article of the present invention, a flexible polyester elastomer resin material is provided not only on a surface having flexibility but also on the reverse surface so as to form a composite materlal wherein the two layers are symmetrically provided about the primary molded sheet. More specifically, in the double molding, etc., this is attained by previously providing a through-hole at a suitable position of the primary molded article or providing a notch at a part of the primary molded article and conducting secondary molding with the primary molded article supported by means of a mold for secondary molding in such a manner that the resin stream of the , ` ~ ;
,' :
secondary material reaches simultaneously both surfaces of the primary molded sheet. In this case, it is not always necessary to cover the whole of both the surfaces of the sheet as the primary molded article with the secondary material, and a surface necessary to have a partlcularly soft part from the viewpoint of design together with the reverse surface at a part substantially corresponding to the above part may be coated with the secondary material, or the secondary material may be provided so as to sandwich the above-described parts of the primary molded sheet.
In this case, both the surfaces of the primary molded sheet need not be always composite-coated similarly to each other. However, from the viewpoint of preventing the warpage, it is desired that both surfaces at respective positions which are symmetrical as much as possible be composited with the secondary material so that both the secondary material layers have substantially the same thickness with each other.
When the secondary material in both the surfaces is in a remarkably unbalanced state in respect of the position, area, thickness, etc., the effect of preventlng the warpage is reduced.
A description will now be given on the primary material and the secondary material. The resin material used as the primary material may be any one as far as it is a resin material mainly composed of a rigid thermoplastlc polyester resin. Fundamentally, however, since the composite molded article of the present invention, as such, should have deflection resistance and be less susceptible to flexing, the polyester resin should have an elastic modulus in bending of 15Q00 kgf/cm2 or more, preferably 20000 kgf/cm2 or more.
Specific examples thereof include polyalkylene terephthalates (with the number of carbon atoms in the alkylene group of 2 to 4) including polybutylene terephthalate and polyethylene terephthalate, known copolymers mainly composed of the polyalkylene terephthalates, and these resin materials blended with a minor amount of other thermoplastic resin as an auxiliary additive.
The primary resin material should be fused by the secondary material in the secondary molding.
Therefore, when the melting point is very high, it becomes necessary to raise the resin temperature of the secondary material in the secondary molding above that temperature. This is liable to bring about thermal decomposition and a remarkable lowering in the viscosity, so that there occurs a problem on the 2~7~29~
molding. For this reason, it is preferred to select a material having a melting point of 230C or below as the primary material. The melting point is particularly preferably 220C or below.
In view of the above, polybutylene terephthalate or a copolymer or a mixture mainly composed of polybutylene terephthalate is preferred as the primary material. There is no particular limitation on the kind of the comonomer, and any known comonomer may be ; 10 used. In general, the amount of incorporation of the comonomer is preferably 40% or less from the viewpoint of the ri.gidity.
In many cases, an inorganic filler is preferably incorporated in the primary material for the purpose of enhancing the mechanical properties and from the viewpoint of the heat resistance (heat deformation temperature), dimensional accuracy, etc., particularly from the viewpoint of increasing the deflection resistance of the final molded article~ Examples of the inorganic filler include fibrous reinforcements such as glass fibers and carbon fibers, glass flakes, glass powders, glass beads, mlca, calcium carbonate and other particulate and flaky fillers. However, the inorganic filler is not limited to these only, and any known inorganic filler may be selected for use in 20702~
imparting an intended property. Two or more inorganic fillers may be used in combination.
Other thermoplastic resin may be incorporated in a minor amount as an auxiliary additive in the primary material. The melting point, rigidity and other properties of the primary materlal may be regulated according to the purpose by the type of the thermoplastic polyester resin used, the type and amount of the comonomer, the type and amount of the thermoplastic resin used as other auxiliary additive and the type and amount of the inorganic filler.
The resin material for forming a flexible surface part of the sheetlike composite molded article according to the present invention is mainly composed of a thermoplastic polyester elastomer and in general the elastic modulus in bending thereof is preferably 10000 kg/cm2 or less from the viewpoint of imparting flexibility, still preferably 7000 kg/cm2 or less.
The polyester elastomer as the main ingredient constituting the secondary material may be any random or block copolyester comprising as the constituent a soft segment such as a polyoxyalkylene glycol ester, and any commercially available polyester elastomer or prepared polyester elastomer may be used.
Representative examples of the polyester 2~7029~
elastomer include a polyester copolymer comprislng a phthalate of polyoxyethylene glycol or polyoxybutylene glycol as the soft segment and butylene terephthalate or ethylene terephthalate as the other constituent.
The polyester elastomer may contain a minor amount of other thermoplastic resin as an auxiliary additive. The flexibility of the surface part of the composite molded article may be adjusted to an intended value through a proper selection of the content of the soft segment, for example, a polyoxyalkylene glycol ester segment, in the polyester elastomer, the molecular weight of the segment, other comonomer component, other auxiliary additive resin or the like.
The sheetlike composite molded article of the present invention is produced by subjecting the above-described rigid primary material to primary molding to form a sheet base molded article and subjecting a secondary material to molding and fusion according to the double molding, etc., so as to substantially symmetrically cover both surfaces of the base molded artlcle at its part which necessitates flexibility.
The resin temperature of the secondary material in the secondary molding should be above the melting point of the primary material, preferably 10 to 70C above the 207~29a melting point of the primary material from the viewpoint of attaining a high fusion.
In the sheetlike composite molded article of the present invention, the use of two particular selected polyester resin materials provides the followlng advantages:
(1) it is less susceptible to flexing as a whole even upon being exposed to a low external force by virtue of its high deflection resistance as a whole, (2) the surface is kept flexlble, (3) the base and the flexible part of the surface are flrmly fused to each other and are less liable to peel, (4) it ls excellent in the mechanical properties, heat resistance and chemical resistance as well, and (5) it is light in weight.
Further, in the secondary molding, since the sheet base molded article is coated on its both surfaces with the secondary material or sandwlched in between the secondary material layers, (6) the warpage is prevented during the molding, so that a sheetlike molded article having accurate dimension and configuration can be produced.
This renders the composite molded article of the , ?:
, ~07029~
present invention suitable for use in many applications where the above described properties are required.
[Brief Description of Drawings]
Fig. 1 is a diagram showing the configuration of a primary molded article used in Examples 1, 2 and 3;
Fig. 2 is a diagram showing the configurahion and structure of the composite molded article according to the present invention (Examples 1, 2 and 3);
Fig. 3 is a diagram showing a composite molded article outside the scope of the present invention (Comparative Examples 1, 2 and 3);
Fig. 4 is a diagram showing the configuration of a primary molded article used in Examples 4 and 5 according to the present invention;
Fig. 5 is a diagram showing the configuration and structure of the composite molded article according to the present invention (Examples 4 and 5); and Fig. 6 is a diagram showing another composite molded article outside the scope of the present invention (Comparative Examples 5 and 6). In the Figs. 1 to 6, (a) is a plan view, (b) is a cross-sectional view taken along line X-X of (a), and (c) is a bottom plan view.
1: primary molded article, 207029~
2: secondary molded article, 3: through hole of primary molded article, and 4: notch of secondary molded article.
[Examples]
The present invention will now be described in more detail with reference to the following Examples, though it is not limited to these only.
Examples 1 to 3 The following materials were used as a primary material and subjected to primary molding to produce boxes having a through hole at the center of the bottom sheet as shown in Fig. 1:
A-1: polybutylene terephthalate resin (melting point: 225C, modulus of elasticity in bending: 26000 kg/cm2), A-2: polybutylene terephthalate resin copolymer containing minor amount of polybutylene isophthalate (melting point: 205C, modulus of elasticity in bendlng: 26000 kg/cm2), A-3: composition comprising the polybutylene terephthalate copolymer resin A-2 and, incorporated therein, 20% of glass fiber and 20% of glass flake (modulus of elasticity in bending: about 90000 kg/cm2)O
Then, the boxy primary molded articles were mounted on 2~702~
a cavity of a mold for secondary molding conducted at a resin temperature of 250C through the use of the following material as a secondary material, thereby producing composite molded articles wherein both surfaces of the bottom sheet of the boxy primary molded article were melt-sandwiched in between the secondary material layers having a substantially equal thickness as shown in Fig. 2:
B-1: polyester elastomer (melting point: 182C, modulus of elasticity in bending: 720 kg/cm2) .
The properties such as the amount of warpage, appearance, flexing resistance and surface hardness after the secondary moldlng were evaluated.
Comparative Examples 1 to 4 Boxy primary molded articles shown in Fig. 1 were molded through the use of the same primary materials as those used in the Examples 1 to 3, i.e., A-1, A-2 and A-3, except that no through hole was provided at the center of the bottom sheet. The primary molded articles were mounted on a mold for secondary side molding and, as shown in Fig. 3, molded articles wherein only one surface was composited with a secondary material comprising the same thermoplastic polyester elastomer as that described in the B-1 were :, , ~ 17 -produced and subjected to the same evaluation as that described above (Comparative Examples 1, 2 and 3).
For comparison, a box having the same shape as that of the composite molded article shown in Fig. 2 was produced by single molding through the use of the secondary material (B-1) without the use of the primary material and evaluated (Comparative Example 4).
Regarding the evaluation method, the appearance was evaluated by judging the gloss, change of color, etc., of the surface of the secondary molded article with the naked eye.
The deflection resistance of the final molded article was evaluated by putting a boxy molded article upside down on a surface plate and touching with a finger to judge the deflection resistance of the bottom sheet by the touch.
The amount of recess (mm) of the center relative to both ends of the bottom sheet of the molded article was measured through the use of a three dimensional sizer, and this value was defined as the amount of warpage. The surface (secondary side) hardness was expressed by Shore hardness D.
The results are also given in Table 1.
~07029~
U~ _ _ _ __ ~' ~5~ o o o o o 'o o a)~ ~ ~r ~r ~r ~r ~r ~
~o ~ _ ~ . ~ _ C~a ~ ~ ~ a~
h ~1 ~1 S~ ~1 . ~ ~J
_ ~ ~
C ~ . . . . . .
O ~ ~ ra ~
~0~ _ _ _ U~ ~ ~ ~ ~ U7 ,~ 3- o _ o ___ o ~-1 ,C ,_ ~ ,~ ~ ~
~LI ~ ~ ~ ~0~ ~ ~ ~
m ~ i l I ~, m l ~s _ _ ~ m E ~ N r~) ~¢ ~f1 a ", _ _ ~1 N ~ ~ (~I ~r) ~r _ _ ~ .. _ X O O ~ O
~Z o1::1Z
Examples 4 and 5 Flat sheets having a notch as shown in Flg. 4 were molded through the use of the following materials as a primary material:
A-4: composition (modulus of elasticity in bending: about 32000 kg/cm2) comprising polybutylene terephthalate copolymer (melting point: 185C) and 5% of glass fiber, A-5: composition (modulus of elasticity in bending: about 80000 kg/cm2) comprising polybutylene terephthalate copolymer of the same type as that of A-4 and 20% of glass fiber and 20% of glass flake.
Then the molded articles were mounted on a mold for secondary side molding conducted at a secondary side resin temperature of 240C through the use of the following material as a secondary material, thereby producing composite molded articles wherein both surfaces of each molded article were substantially symmetrically melt-coated with the secondary material layers as shown in Fig. 5:
B-2: polyester elastomer (melting point: 198C, modulus of elasticity in bending: 1100 kg/cm2).
207~290 The evaluation was conducted in the same manner as that described above.
Comparative Examples 5 to 7 Boxy primary molded articles shown in Fig. 4 were molded through the use of the same primary materials as those used in the Examples 4 and 5, i.e., A-4 and A-5, except that no notch was provided. The primary molded articles were mounted on a mold for secondary molding and, as shown in Fig. 6, molded articles wherein or.ly one surface was composited with a secondary material comprising the same thermoplastic polyester elastomer as that described in the B-2 were produced and subjected to the same evaluation as that described above (Comparative Examples 5 and 6).
For comparison, a box having the same shape as that of the composite molded article shown in Fig. 5 was produced by single molding through the use of the secondary material ~B-2) without the use of the primary material and subjected to evaluation (Comparative Example 7).
The results are given in Table 2.
The composite molded article was curved by hand and the flexing resistance was evaluated by the touch.
, 2~7029~
a ~ _--~ 0~ ~
o ~ I ~ l I ~ l ~ ~ o ~1 ~
_ _ _ a x o ~ x o r~ z c~ ~ æ
Claims (7)
1. A process for producing a composite molded article less susceptible to warpage and having a flexing resistance as a whole and a flexible sheetlike part on its surface, comprising subjecting a resin material mainly composed of a flexible thermoplastic polyester elastomer as a secondary molding material to composite molding by double molding or two-color molding on a base molded article mainly composed of a rigid thermoplastic polyester as a primary molded article, thereby producing a composite molded article in sheet form or having a sheetlike part, characterized in that both surfaces of the sheetlike part in the primary molded article are subjected to secondary molding in such a manner that the sheetlike part is substantially symmetrically fusion-coated on its both surfaces with the secondary material or sandwiched in between the secondary material layers.
2. A process according to claim 1, wherein the resin material mainly composed of a rigid thermoplastic polyester constituting the primary molded article has an elastic modulus in bending of 15000 kg/cm2 or more.
3. A process according to claim 1, wherein the resin material mainly composed of a rigid thermoplastic polyester constituting the primary molded article has a melting point of 230°C or below.
4. A process according to claim 1, wherein the rigid thermoplastic polyester constituting the primary material is a polyalkylene terephthalate (having 2 to 4 carbon atoms in its alkylene group) or a copolymer or a mixture mainly composed of said polyalkylene terephthalate.
5. A process according to claim 1, wherein the rigid thermoplastic resin material constituting the primary molded article is a polyester resin containing an inorganic filler.
6. A process according to claim 1, wherein the resin material mainly composed of a polyester elastomer used in the secondary molding has an elastic modulus in bending of 10000 kg/cm2 or less.
7. A composite molded article having a sheetlike part molded by a process according to claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2267308A JPH0813535B2 (en) | 1990-10-03 | 1990-10-03 | Plate-shaped composite molded article and manufacturing method thereof |
| JP267308/90 | 1990-10-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2070290A1 true CA2070290A1 (en) | 1992-04-04 |
Family
ID=17443023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2070290 Abandoned CA2070290A1 (en) | 1990-10-03 | 1991-10-03 | Sheetlike composite molded article and process for producing the same |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH0813535B2 (en) |
| CA (1) | CA2070290A1 (en) |
| WO (1) | WO1992005938A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3325102B2 (en) * | 1993-12-17 | 2002-09-17 | ポリプラスチックス株式会社 | Polyester-based composite molded article and method for producing the same |
| JP3315570B2 (en) * | 1995-11-27 | 2002-08-19 | ポリプラスチックス株式会社 | Manufacturing method of polyester-based composite molded products |
| JPH10318268A (en) * | 1997-03-18 | 1998-12-02 | Nippon Seiko Kk | Seal for rolling bearing |
| GB2355116B (en) * | 1999-10-08 | 2003-10-08 | Nokia Mobile Phones Ltd | An antenna assembly and method of construction |
| JP5006672B2 (en) * | 2007-03-06 | 2012-08-22 | 株式会社ニコン | Outer shell part of electronic device, manufacturing method thereof, and electronic device provided with outer shell part |
| ITPD20090042A1 (en) | 2009-03-10 | 2010-09-11 | Meccanica Breganzese S P A In Brev E Mb S P A | QUICK ATTACHMENT DEVICE BETWEEN THE ARM OF AN ARM OPERATING MACHINE, IN PARTICULAR THE ARM OF AN EXCAVATOR, AND AN EQUIPMENT TO IT REALLY ASSOCIATED, IN PARTICULAR A BUCKET AND SIMILAR. |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5525057B2 (en) * | 1972-08-07 | 1980-07-03 | ||
| JPS5716317U (en) * | 1980-07-01 | 1982-01-27 | ||
| JPS6050127B2 (en) * | 1981-07-22 | 1985-11-07 | 宮川化成工業株式会社 | Method for manufacturing storage battery containers |
| FR2529507A1 (en) * | 1982-07-05 | 1984-01-06 | Cibie Projecteurs | METHOD FOR MANUFACTURING INJECTION-MOLDING SHAPED ARTICLE AND ARTICLE OBTAINED |
| JPS6471716A (en) * | 1987-09-11 | 1989-03-16 | Tokyo Electric Co Ltd | Two-material molding |
| JPH02184427A (en) * | 1989-01-11 | 1990-07-18 | Fuji Photo Film Co Ltd | Laminate |
-
1990
- 1990-10-03 JP JP2267308A patent/JPH0813535B2/en not_active Expired - Fee Related
-
1991
- 1991-10-03 WO PCT/JP1991/001339 patent/WO1992005938A1/en active Application Filing
- 1991-10-03 CA CA 2070290 patent/CA2070290A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04142935A (en) | 1992-05-15 |
| WO1992005938A1 (en) | 1992-04-16 |
| JPH0813535B2 (en) | 1996-02-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4950532A (en) | Process for producing glass fiber reinforced thermoplastic compression molded materials and said molded materials | |
| Harper et al. | Plastics materials and processes: a concise encyclopedia | |
| KR100505822B1 (en) | Sheet for decorating insert simultaneously with the molding, decorating insert molded product and method for decorating insert simultaneously with the molding | |
| TWI238117B (en) | Composite article made from polyacetal and from styrene-olefin elastomers | |
| KR102463607B1 (en) | Polypropylene-based composite resin composition having fiber texture | |
| AU7638796A (en) | Propylene composition, process for preparing the same, polypropylene composition, and molded articles | |
| JPH04119810A (en) | Polyester composite molded form and manufacture thereof | |
| US5712003A (en) | Blow-molded articles for automobile exterior parts and the process therefor | |
| EP0412779B1 (en) | Surface-patterned polybutylene terephthalate resin molded articles and process for preparing such molded articles | |
| CA2051131A1 (en) | Polypropylene-based resin composition | |
| CA2070290A1 (en) | Sheetlike composite molded article and process for producing the same | |
| EP0407193B1 (en) | Surface-patterned polybutylene terephthalate resin molded articles and process for preparing such molded articles | |
| EP0668142A1 (en) | Method for coextrusion thermoformable panels | |
| MY129969A (en) | Resin with improved thermoforming and environmental stress crack resistance characteristics | |
| JPH0267326A (en) | Fiber-reinforced thermoplastic resin composition with excellent surface flatness | |
| JP2591528B2 (en) | Composite molded operation buttons | |
| US20070166561A1 (en) | Composite bodies, method for the production thereof and use thereof | |
| US5681887A (en) | Method of stamping composite sheets | |
| JP2659273B2 (en) | Synthetic resin clip | |
| JP2574062B2 (en) | Synthetic resin handles | |
| JPS6191256A (en) | Sheet molding compound | |
| JP3802638B2 (en) | Double layer molding | |
| JPH06143331A (en) | Synthetic resin molded article and manufacture thereof | |
| JPS6347965Y2 (en) | ||
| KR19990051234A (en) | White Multilayer Polyolefin Film for Packaging Materials |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |