JP2001062962A - Laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a surface hardness without impairing excellent impact resistant strength to be incorporated in future by providing a resin layer made of a mixture of a polymethacrylate and a phenoxy resin on both or one side surface of a base material of a polyester polymer containing a polyethylene terephthalate as a basic structure. SOLUTION: A resin layer made of a mixture of a polymethacrylate (PMMA) and a phenoxy resin is arranged on both or one side surface of a base material of a polyester polymer containing a polyethylene terephthalate as a basic structure, and co-extruded. A mixing ratio of the phenoxy resin to the PMMA is preferably 5 wt.% or more. The laminated sheet is manufactured in combination of a main extruder for normally forming a base material from the polyester polymer, and a sub-extruder for forming the resin layer of a coating layer of the base material from the mixture of the PMMA and the phenoxy resin. A thickness of the sheet is normally 0.1 to 20 mm. A thickness of the coating layer is normally preferred at 50 to 100 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester polymer suitable for applications such as outdoor signboards, highway noise barriers and other building materials used outdoors, mechanical covers, game machine covers, and in-store decorative displays. The present invention relates to a laminated sheet including a base material, a method for producing the same, and a resin molded product comprising the laminated sheet.

[0002]

2. Description of the Related Art Polymethyl methacrylate (PMMA), polycarbonate (PMMA), polycarbonate (PMMA), and other materials for construction materials used outdoors such as outdoor signboards, highway noise insulation walls, and the like, or interior decoration materials and the like that require translucency are conventionally used. Sheets such as PC), polyvinyl chloride (PVC) have been widely used. In recent years, polyethylene terephthalate (PET) and copolymerized polyester of polyethylene terephthalate and cyclohexane dimethanol (PET) have been mainly used for machine covers, game machine covers, indoor decorative displays, and the like.
Sheets of polyester-based polymers such as G) have also become widespread.

[0003] However, although PMMA is excellent in weather resistance, transparency and surface hardness, it has the disadvantage that it has low impact strength and is easily broken. On the other hand, PC is PMMA
As compared with the above, although the impact resistance is excellent, the weather resistance and the surface hardness are inferior, and there is a problem that the material absorbs moisture and foams due to heating during the secondary processing such as vacuum forming. In addition, the use of PVC has been shunned as public opinion raises concerns about pollution during disposal and incineration.

[0004] Although the polyester-based polymer sheet is excellent in impact strength and secondary workability, it has a drawback that it is inferior in weather resistance and surface hardness. As an attempt to solve the drawbacks of the polyester polymer sheet, there has been proposed a laminated sheet in which a PMMA layer is disposed on the surface of the polymer sheet and laminated and integrated (Japanese Patent Laid-Open No. 8-142279). However, such a laminated sheet has a problem that the adhesiveness between the polyester polymer sheet and the PMMA layer is not sufficient, and the laminated sheet is easily peeled.

As another attempt, there has been proposed a laminated sheet in which PC is disposed as an adhesive layer between a polyester polymer sheet and a PMMA layer and laminated and integrated (Japanese Patent Laid-Open No. Hei 8-290532). ). This laminated sheet is manufactured by arranging a layer of PC between the polyester-based polymer sheet and the PMMA layer and coextruding them integrally. In the production of a laminated sheet by co-extrusion, generally, sheet-like resin laminated and integrated in a molten state is cooled by passing through three or four polishing rolls. The polishing roll not only cools the sheet, but also adjusts the sheet thickness, polishes the surface, and corrects warpage and distortion. It is a well-known technical matter that the setting of the temperature of the polishing roll is an important point for obtaining a sheet having good gloss and excellent appearance on the sheet surface without warpage or distortion.

However, according to the study results of the present inventors, during co-extrusion, the temperature of the polishing roll is set to PC.
However, since this temperature is about 50 ° C. higher than the glass transition temperature of PMMA, the surface PMMA layer is not sufficiently cooled, and the adhesion to the polishing roll is increased. This causes a problem of appearance failure. On the other hand, when the temperature of the polishing roll is set low, the PC layer becomes excessively cooled, and the warpage and distortion of the sheet increase, so that a good laminated sheet cannot be obtained. In addition, when performing secondary processing such as vacuum forming on the laminated sheet, it is necessary to heat to the forming temperature of PC, so that the original workability of the polyester-based copolymer resin sheet is sacrificed, Because the time is long,
The foaming phenomenon accompanying the moisture absorption of the PC layer may occur, which is not preferable.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laminated sheet having a high surface hardness without impairing the excellent impact resistance inherent in a polyester resin sheet.

[0008]

According to the present invention, the above-mentioned object is achieved by a resin layer comprising a mixture of polymethyl methacrylate and a phenoxy resin on both sides or one side of a polyester polymer base material having a basic structure of polyethylene terephthalate. Can be achieved by a laminated sheet excluding the above.

According to the present invention, such a laminated sheet is formed by disposing a resin layer made of a mixture of polymethyl methacrylate and a phenoxy resin on both or one side of a polyester polymer base material having a basic structure of polyethylene terephthalate. Can be produced by co-extrusion.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. A feature of the laminated sheet of the present invention resides in that a resin composition comprising a mixture of PMMA and a phenoxy resin is used for a layer covering a polyester-based copolymer substrate. PM
By mixing phenoxy resin with MA, PMMA
Can impart adhesion performance to a polyester copolymer without impairing the transparency and surface hardness of the polyester.

In the present invention, the polyester polymer which can be a base material constituting the laminated sheet has a basic structure of polyethylene terephthalate composed of a dicarboxylic acid unit mainly composed of terephthalic acid units and a diol unit mainly composed of ethylene glycol units. Typical examples thereof include polyethylene terephthalate consisting of only terephthalic acid units and ethylene glycol units, but are not limited to polyethylene terephthalate, and may be 20 mol% or less in all structural units. If necessary, polyethylene terephthalate having another dicarboxylic acid unit and / or diol unit may be used.

Examples of other dicarboxylic acid units which may be contained in polyethylene terephthalate include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl)
Aromatic dicarboxylic acids such as methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, and sodium 5-sulfoisophthalate; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and dodecandioic acid; -Cyclohexanedicarboxylic acid,
Alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; and dicarboxylic acid units derived from ester-forming derivatives thereof (lower alkyl esters such as methyl ester and ethyl ester). Polyethylene terephthalate may have one kind of the above-mentioned dicarboxylic acid units, or may have two or more kinds.

Examples of other diol units that can be contained in polyethylene terephthalate include 1,4-butanediol, ethylene glycol, propylene glycol,
C2-10 carbon atoms such as neopentyl glycol, 2-methylpropanediol, 1,5-pentanediol, cyclohexanedimethanol, cyclohexanediol, etc.
Aliphatic diols; diethylene glycol, polybutylene glycol, poly-1,3-propylene glycol,
Examples thereof include diol units derived from polyalkylene glycol having a molecular weight of 6000 or less such as polytetramethylene glycol. Polyethylene terephthalate may have only one kind of the above-mentioned diol unit, or may have two or more kinds.

Further, polyethylene terephthalate is derived from a trifunctional or higher functional monomer such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid and pyromellitic acid, if it is 1 mol% or less based on the total structural units. It may have one or more structural units.

The production of a substrate from polyethylene terephthalate can be easily carried out, for example, by melting and cooling polyethylene terephthalate. At that time, by rapidly cooling the polyethylene terephthalate in a molten state, crystallization of polyethylene terephthalate, which is originally crystalline, is inhibited, and a substrate having excellent transparency can be obtained. More specifically, it is preferable that the polyethylene terephthalate is melt-extruded into a sheet, brought into contact with a polishing roll, and rapidly cooled.

Further, by copolymerizing polyethylene terephthalate with other copolymerization components such as isophthalic acid, neopentylene glycol, and cyclohexane dimethanol, the crystallization of the polyester polymer in the cooling process can be delayed, This is particularly advantageous because a substrate having excellent transparency can be obtained regardless of the cooling rate after melt extrusion. From this viewpoint, a copolymer of polyethylene terephthalate that can be particularly preferably used is a copolymerized polyester of polyethylene terephthalate and cyclohexanedimethanol (PETG).

In the present invention, polymethyl methacrylate is a homopolymer composed of a structural unit derived from methyl methacrylate, or composed of 50% by weight or more of a structural unit derived from methyl methacrylate and copolymerizable with methyl methacrylate. It is a copolymer containing a structural unit derived from a monomer. Examples of monomers copolymerizable with methyl methacrylate include methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
More than one species may be used.

The method for producing polymethyl methacrylate is not particularly limited, and it can be produced by a known method such as suspension polymerization. Polymethyl methacrylate can be kneaded and melted by a screw extruder and extruded from a die into a plate to form a sheet. Various additives generally used for hard acrylic resins can be added to polymethyl methacrylate, and examples of the additives include an antioxidant, a flame retardant, and a colorant.

Polymethyl methacrylate may be added with a multi-layer acrylic particulate elastic material for the purpose of improving the impact resistance of the laminated sheet of the present invention. Here, the multi-layered acrylic granular elastic body is a granular acrylic polymer having at least a two-layer structure having a structure in which a hard layer polymer and a soft polymer having rubber-like properties are layered. The multi-layered acrylic granular elastic body is not particularly limited as long as it has such a layered structure. However, if the average particle diameter becomes too large, stress whitening occurs. It is preferable that the thickness be in the range of 1 to 0.3 μm.

In the production of the multi-layered acrylic granular elastic material, the monomer mixture constituting each layer is successively added from the inner layer.
A method such as emulsion polymerization is used, but it is not particularly limited to this production method. As the hard layer polymer constituting the multi-layer acrylic granular elastic body, the main component is methyl methacrylate, and the alkyl group copolymerizable with this has 1 carbon atom.
Polymers obtained by polymerizing a mixture of acrylates and grafting monomers of Nos. To 8 are preferably used.

Examples of the acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate and butyl acrylate. Also,
As the grafting monomer, allyl methacrylate, diallyl methacrylate and the like are preferably used.

Examples of the soft polymer having rubber-like properties constituting the multi-layered acrylic granular elastic material include, in the presence of the above-mentioned hard polymer, an acrylate having 1 to 8 carbon atoms of an alkyl group, A polymer obtained by polymerizing a mixture of a functional crosslinking agent and / or a grafting monomer is preferably used. As the polyfunctional crosslinking agent, a diallyl compound, a diacryl compound, or the like is usually used. Further, as the grafting monomer, allyl methacrylate, diallyl methacrylate and the like are preferably used.

It is desirable that the weight ratio of the soft polymer in the multi-layer acrylic particulate elastic material is 20 to 60% by weight. When the proportion of the soft polymer is less than 20% by weight, sufficient impact resistance may not be provided. On the other hand, when the proportion by weight of the soft polymer exceeds 60% by weight, the corresponding whitening property is reduced. May drop.

In the present invention, the resin layer composed of a mixture of polymethyl methacrylate and phenoxy resin can further contain an ultraviolet absorber, whereby the weather resistance of the laminated sheet can be improved. There is no particular limitation on the type of the ultraviolet absorber, and examples thereof include known ultraviolet absorbers such as benzotriazole, hindered amine, and benzophenone. One or two or more ultraviolet absorbers can be used.

The content of the ultraviolet absorber is preferably 0.5 to 2.0% by weight based on polymethyl methacrylate,
Particularly preferably, it is 1.0 to 1.5% by weight. When the content of the ultraviolet absorbent is less than 0.5% by weight, it may not be possible to obtain weather resistance enough to withstand outdoor use. On the other hand, even if the content exceeds 2.0% by weight, However, it is difficult to say that the effect is justified in proportion to the increase in costs associated with the increase in the content.On the other hand, the excess content causes slipping in the extruder or contamination of the polishing roll by volatile components. Adversely occurs, which is not preferable.

The phenoxy resin used in the present invention is a high molecular weight polyhydroxy polyether synthesized from bisphenol A and epichlorohydrin.

The mixing ratio of the phenoxy resin to PMMA is preferably at least 5% by weight. If the mixing ratio of the phenoxy resin is less than 5% by weight, the adhesiveness to the polyester polymer tends to decrease. As the mixing ratio of the phenoxy resin increases, the adhesive strength with the polyester-based polymer improves, but even if it exceeds 50% by weight, a significant improvement in the adhesive strength cannot be expected, and conversely, the weather resistance tends to be impaired. Is seen. From the above points, the preferred mixing ratio of the phenoxy resin to PMMA is 5% by weight or more.
50% by weight.

The mixing of PMMA and the phenoxy resin can be carried out using a single screw extruder, a twin screw extruder or the like which is usually used for mixing polymers. The laminated sheet of the present invention,
The glass transition temperature of the mixture of PMMA and the phenoxy resin is relatively close to that of the polyester copolymer, and there is no need to raise the temperature of the polishing roll during co-extrusion, so there is no appearance defect associated with adhesion to the polishing roll. It is excellent in that warpage and distortion are small. Furthermore, since the laminated sheet of the present invention does not need to raise the molding temperature when performing secondary processing such as vacuum molding, the workability inherent to the polyester-based copolymer sheet is not impaired. It is also excellent.

In the production of the laminated sheet of the present invention, a main extruder for forming a base material from a polyester polymer and a resin layer which is a coating layer of the base material are formed from a mixture of PMMA and a phenoxy resin. This is performed using two extruders that are combined with a sub-extruder for performing the above. As the sub-extruder, an extruder smaller than the main extruder is generally used.

In producing the laminated sheet of the present invention, as a lamination method, a known method such as a feed block method or a multi-manifold method can be adopted. The resin laminated by the feed block is guided to a sheet forming die such as a T die, formed into a sheet, and then flows into a forming roll (polishing roll) having a mirror-finished surface to form a bank. The sheet is mirror-finished while passing through a forming roll, and can be a laminated sheet having excellent appearance.

The resin laminated in the multi-manifold die is similarly formed into a sheet inside the die.
Then, the surface is finished by a forming roll and further cooled, and a laminated sheet having excellent appearance can be obtained. The thickness of the laminated sheet is not particularly limited, but is usually 0.1
It is in the range of ２０20 mm. The thickness of the coating layer is not particularly limited, but is preferably in the range of usually 50 to 100 μm. The thickness of the laminated sheet can be adjusted by the gap between the rolls, and the ratio of the thickness of each layer can be adjusted by changing the ratio of the amount of extrusion in each extruder.

The laminated sheet thus obtained can be used as a flat plate, or can be formed on a curved surface such as a corrugated sheet by performing secondary forming, or can be given a shape by vacuum forming or the like. It can be formed into a molded product.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In the following Examples and Comparative Examples, adhesion (delamination), total light transmittance, haze (%), Izod impact strength, and surface hardness were measured or evaluated as follows.

(1) Adhesion (Delamination) The laminated sheets produced in the following Examples or Comparative Examples were subjected to a three-point bending test by an autograph, and the presence or absence of delamination at break was visually determined. (2) Total light transmittance and haze (%) For the laminated sheet manufactured in the following example or comparative example, a direct-reading haze meter (HG manufactured by Suga Test Instruments Co., Ltd.)
M-2DP), the total light transmittance and haze in the thickness direction were measured at a measurement temperature of 20 ° C. (3) Izod impact strength 23 ° C. using an Izod impact strength tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.) according to JIS K7110 using the laminated sheet manufactured in the following example or comparative example.
The notched and unnotched Izod impact strength was measured. (4) Surface Hardness The surface hardness (pencil hardness) of the laminated sheet manufactured in the following example or comparative example was measured according to JIS K5400.
Was measured.

The contents of the polyester polymer, PMMA, phenoxy resin and polycarbonate used in these Examples and Comparative Examples are as follows. Polyester-based polymer 1: a copolymer comprising polyethylene terephthalate, cyclohexanedimethanol, and trimellitic acid. Using a differential calorimeter (DSC), it was confirmed from the endothermic peak curve when the temperature was raised from 20 ° C. to 250 ° C. at a rate of 10 ° C./min that a main endothermic peak was present at 220 ° C. Polyester polymer 2: Eastman Chemical Co., Ltd.
"Spectar copolyester 14471". Using a differential calorimeter (DSC), the temperature was raised from 20 ° C at a rate of 10 ° C /
The main endothermic peak was not recognized in the endothermic peak curve when the temperature was raised to 250 ° C. in minutes. PMMA: Kuraray Co., Ltd. “Parapet HR1000
S "Phenoxy resin:" Phenototo Y "manufactured by Toto Kasei Co., Ltd.
P-50S ”Polycarbonate:“ Calibur 30 ”manufactured by Sumitomo Dow
1-30 "

Production Example [Production of mixture of PMMA and phenoxy resin] PMMA and phenoxy resin were mixed with a tumbler, and
It was put into a 30 mm twin screw extruder, melted and kneaded, and extruded from a strand die. The strand was cooled with water, cut with a pelletizer, and processed into a pellet. Pellets were produced by changing the ratio of the phenoxy resin to PMMA to 5, 10, and 30% by weight. In each case, the pellets were excellent in transparency.

Example 1 A polyester polymer 1 was extruded at a rate of 20 kg / hr from a single screw extruder (main extruder) having a diameter of 40 mm, while a PM was fed from a single screw extruder (sub extruder) having a diameter of 22 mm.
Mixture of MA and phenoxy resin (mixing ratio: PMMA /
(Phenoxy resin = 95/5% by weight) was extruded at a rate of 2 kg / hr. These extruded layered materials were combined in a feed block and led to a 200 mm wide sheet manufacturing die to form a laminated sheet. Thereafter, the laminated resin discharged from the die is passed through a polishing roll adjusted so that the total thickness of the laminated sheet becomes 2 mm, thereby cooling and mirror-finish the laminated sheet, thereby forming the intended two-layer laminated sheet. Obtained. The thickness of the resin layer made of the mixture of PMMA and the phenoxy resin in the obtained laminated sheet was 50 μm.

Example 2 The mixing ratio of the mixture of PMMA and phenoxy resin supplied to the sub-extruder was changed to PMMA / phenoxy resin = 90/10
A two-layer laminated sheet was obtained in the same manner as in Example 1 except that the weight% was changed.

Example 3 The mixing ratio of the mixture of PMMA and phenoxy resin supplied to the sub-extruder was set to be PMMA / phenoxy resin = 70/30.
A two-layer laminated sheet was obtained in the same manner as in Example 1 except that the weight was changed.

Example 4 A two-layer laminated sheet was obtained in the same manner as in Example 1 except that the polyester polymer supplied to the main extruder was changed to the polyester polymer 2. The laminated sheets obtained in Examples 1 to 4 were transparent, did not show any poor appearance due to the adhesion of the polishing roll, had no warpage or distortion, and had an extremely good appearance. The laminated sheets obtained in Examples 1 to 3 were examined for adhesion (delamination), total light transmittance, haze (%), Izod impact strength, and surface hardness. .

Comparative Example 1 The polyester polymer 1 was extruded at a rate of 20 kg / hr from a single screw extruder (main extruder) of φ40 mm, while 2 kg of PMMA was extruded from a single screw extruder (sub extruder 1) of φ22 mm. / Hr in a feed block, the polyester polymer and PMMA were merged in this order in the feed block and led to a 200 mm wide sheet manufacturing die to form a laminated sheet. Thereafter, the laminated resin discharged from the die was passed through a polishing roll adjusted so that the total thickness of the laminated sheet was 2 mm, whereby the laminated sheet was cooled and mirror-finished to obtain a two-layer laminated sheet. The thickness of the PMMA layer in the obtained laminated sheet was 50 μm. The obtained laminated sheet was transparent, did not show any warpage, and did not show any poor appearance due to poor peeling from the polishing roll, and had a good appearance.

Comparative Example 2 The procedure of Comparative Example 1 was repeated except that the polyester polymer supplied to the main extruder was changed to a polyester polymer 2.
A two-layer laminated sheet was obtained. With respect to the laminated sheets obtained in Comparative Examples 1 and 2, adhesiveness (delamination), total light transmittance,
When the haze (%), the Izod impact strength, and the surface hardness were examined, the results were as shown in Table 1.

Comparative Example 3 A polyester polymer 2 was extruded from a φ40 mm single screw extruder, processed into a sheet shape by a die for manufacturing a sheet having a width of 200 mm, and passed through a polishing roll adjusted to a plate thickness of 2 mm. By doing so, cooling and mirror finishing were performed to obtain a single-layer sheet made of a polyester polymer having a thickness of 2 mm. The laminated sheets obtained in Comparative Examples 1 to 3 were examined for adhesion (delamination), total light transmittance, haze (%), Izod impact strength, and surface hardness. .

[0044]

[Table 1]

[0045]

The laminated sheet of the present invention is characterized in that a resin layer comprising a mixture of polymethyl methacrylate and a phenoxy resin is disposed on both or one side of a polyester polymer substrate having a basic structure of polyethylene terephthalate.
Adhesion between layers can be improved, and by mixing phenoxy resin with polymethyl methacrylate, sheet warpage and poor appearance can occur during the cooling process by the polishing roll during co-extrusion. Not good. Further, the laminated sheet of the present invention is also excellent in that the surface hardness can be improved without impairing the impact resistance and transparency inherently provided by the polyester polymer. Therefore, the laminated sheet of the present invention can be used extremely effectively for a wide range of applications such as building materials used outdoors such as outdoor signboards and highway noise insulation walls, mechanical covers, game machine covers, and in-store decorative displays.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 33/12 C08L 33/12 71/10 71/10 // B29K 33:00 67:00 71:00 B29L 9:00 F term (reference) 4F100 AK25B AK25C AK42A AK54B AK54C AL05B AL05C BA02 BA03 BA06 BA10B BA10C BA13 DD12 EH202 EJ192 EJ272 GB07 GB48 GB51 GB90 JK06 JK10 JK12 JK16 JL04 JN01 4F207 AA21A23A23A23A23 KL84 4J002 BG06W CH08X GT00

Claims (4)

[Claims] 1. A laminated sheet comprising a polyester polymer base material having a basic structure of polyethylene terephthalate and a resin layer made of a mixture of polymethyl methacrylate and a phenoxy resin disposed on both surfaces or one surface of the substrate. 2. A resin layer comprising a mixture of polymethyl methacrylate and a phenoxy resin is disposed on both sides or one side of a base material of a polyester polymer having a basic structure of polyethylene terephthalate, and is co-extruded integrally. A method for manufacturing a laminated sheet. 3. A resin molded article comprising the laminated sheet according to claim 1. 4. The resin molded product according to claim 3, wherein the resin molded product is formed into a corrugated shape.