JP2003191399A - Transparent synthetic resin laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent synthetic resin laminated sheet which provides the same adhesive strength, impact strength and other physical properties as those of a synthetic resin laminated sheet prepared by using a polyurethane adhesive with good adhesive properties, while its manufacturing cost is reduced. <P>SOLUTION: The transparent synthetic resin laminated sheet has a constitution wherein a bottom sheet layer 1 of a polycarbonate resin, an intermediate film layer 3 of a thermoplastic resin and a top sheet layer 2 of an acrylic resin are integrally stuck together through a hot-melt type resin adhesive layer 4 in which an ethylene-vinyl acetate copolymer and/or a saponified ethylene-vinyl acetate copolymer are main ingredients. When the bottom sheet layer 1 and the top sheet layer 2 are stuck together with the hot-melt type resin adhesive layer alone, it is impossible to obtain the same adhesive strength as that of the laminated sheet adhered with the polyurethane adhesive, however, when adhesion is performed by placing the intermediate film layer 3 of the thermoplastic resin between them, the synthetic resin laminated sheet with the same adhesive strength as or a higher adhesive strength than that of the polyurethane adhesive is obtained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a transparent synthetic resin laminate mainly used as a safety cover material for machine tools and the like.

[0002]

2. Description of the Related Art Conventionally, as a safety cover material for machine tools and the like, a transparent synthetic resin laminated plate in which a polycarbonate resin plate and an acrylic resin plate are bonded together with a thermoplastic polyurethane adhesive has been known.

This synthetic resin laminate has a high adhesive strength between a polycarbonate resin plate and an acrylic resin plate, good impact resistance and other physical properties, and is a highly safe composite having the advantages of both resin plates. It is a plate.

[0004]

However, the above-mentioned synthetic resin laminated plate has a problem that the manufacturing cost becomes high because the polyurethane adhesive used is expensive. However, if other adhesives that can be obtained at a relatively low cost are used to reduce costs, a synthetic resin that has the same adhesive strength and impact resistance as the synthetic resin laminate using the polyurethane adhesive described above. It becomes difficult to obtain a laminated board.

The present invention has been made to cope with such a situation, and its object is to provide the same adhesive strength, impact strength and other physical properties as those of a synthetic resin laminate using a polyurethane adhesive. Moreover, it is to provide a transparent synthetic resin laminated plate capable of reducing the manufacturing cost.

[0006]

In order to achieve the above object, a synthetic resin laminate according to claim 1 of the present invention comprises a lower layer of a polycarbonate resin, an intermediate film layer of a thermoplastic resin, and an acrylic resin. The upper plate layer and the ethylene-vinyl acetate copolymer and / or a saponified ethylene-vinyl acetate copolymer is a main component of the hot-melt type resin adhesive layer is adhered integrally. It is a feature.

A hot-melt type resin adhesive containing an ethylene-vinyl acetate copolymer and / or a saponified ethylene-vinyl acetate copolymer as a main component has a functional group such as a carboxyl group or a hydroxyl group in the polymer molecule. Therefore, the adhesiveness is good, but when the lower plate layer of the polycarbonate resin and the upper plate layer of the acrylic resin are integrally bonded only with this adhesive, the impact strength becomes insufficient as shown in the experimental data described later, and cracks occur. Therefore, it is difficult to obtain a synthetic resin laminate having the same impact strength as that of the synthetic resin laminate adhered using the above-mentioned polyurethane adhesive. However, when an intermediate film layer of a thermoplastic resin is provided between the lower plate layer and the upper plate layer as in the present invention, and these are integrally bonded via the above hot melt resin adhesive,
As shown in the experimental data described later, the impact resistance is improved, and a highly safe synthetic resin laminate having the same adhesive strength and impact resistance as the synthetic resin laminate using the polyurethane adhesive described above can be obtained. . Moreover, the above hot-melt resin adhesive is available at a considerably lower cost than the above-mentioned polyurethane-based adhesive, and the intermediate film of the thermoplastic resin is also inexpensive, so the synthetic resin laminate of the present invention is The manufacturing cost can be reduced.

Next, a synthetic resin laminate according to a second aspect of the present invention is the same as the synthetic resin laminate according to the first aspect, in which a plurality of the intermediate film layers are provided via the resin adhesive layer. It is characterized by that.

Such a synthetic resin laminated plate also has the same adhesive strength and impact strength as the synthetic resin laminated plate using the above-mentioned polyurethane adhesive, and the manufacturing cost can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a synthetic resin laminated plate according to an embodiment of the present invention.

This synthetic resin laminated plate comprises a transparent polycarbonate resin lower plate layer 1, a transparent thermoplastic resin intermediate film layer 3 and a transparent acrylic resin upper plate layer 2, and a transparent hot melt type. It is a transparent laminated plate integrally bonded via the resin adhesive layers 4 and 4.

The lower plate layer 1 of the polycarbonate resin serves to improve the penetration resistance of the synthetic resin laminated plate by the excellent impact resistance inherent in the polycarbonate resin and to ensure the safety, so that, for example, a machine tool or the like. In the case of the synthetic resin laminated plate used as the safety cover material, a thick polycarbonate resin plate having a thickness of at least 5 mm, preferably about 6 to 10 mm is used as the lower plate layer 1.

On the other hand, the upper layer 2 of the acrylic resin serves to improve the scratch resistance of the upper surface of the synthetic resin laminated plate due to the inherently high surface hardness of the acrylic resin.
It is sufficient to be thinner than the lower plate layer 1 described above, and for example, a polymethylmethacrylate plate having a thickness of less than 5 mm, preferably about 2 to 4 mm is used. In particular, when a cast type polymethylmethacrylate plate having good oil resistance is used, it is possible to improve the oil resistance of the upper surface of the synthetic resin laminate.

The thermoplastic resin intermediate film layer 3 enhances the impact resistance strength of the synthetic resin laminate, and when the impact force is applied from the outside (especially from the top plate layer 2), the acrylic resin top plate layer 2 is formed. And serves to prevent the lower plate layer 1 of the polycarbonate resin from cracking or cracking,
For example, polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PM
Films such as MA) and polyvinyl chloride (PVC) are used. As the PET film, a stretched PET film or an amorphous PET film (10 to 70% of PET ethylene glycol component replaced with cyclohexanedimethanol) is preferably used.
Particularly preferred is a biaxially stretched PET film.

The thickness of the intermediate film layer 3 is 50 to 20.
The thickness is preferably about 0 μm, and when the thickness is less than 50 μm, it becomes difficult to sufficiently increase the impact resistance of the synthetic resin laminate, and when the thickness is more than 200 μm, PE
When the intermediate film layer 3 is formed of a relatively strong film such as a T film, it becomes difficult to sufficiently increase the impact strength. The more preferable thickness of the intermediate film layer 3 is 70 to 150 μm, and the impact resistance strength is improved by forming it in multiple layers.

The hot melt type resin adhesive layer 4 is mainly composed of an ethylene-vinyl acetate copolymer and / or a saponified ethylene-vinyl acetate copolymer, and the former ethylene-vinyl acetate copolymer is used. Polymer (hereinafter, EV
A) has a carboxyl group as a functional group, and the latter saponified ethylene-vinyl acetate copolymer (hereinafter, referred to as saponified EVA) has a carboxyl group and a hydroxyl group as a functional group, and therefore has good adhesion. Shows sex. The former EVA
Is preferably 10 to 40% by weight of vinyl acetate,
Further, the latter saponified EVA preferably contains 5 to 30% by weight of vinyl acetate and 5 to 30% by weight of vinyl alcohol.

If desired, the hot melt resin adhesive may be further mixed with a modifier or a tackifier.
As the modifier, a graft copolymer of a methacrylic acid ester-unsaturated carboxylic acid copolymer component and an ethylene-vinyl acetate copolymer component, or a saponified copolymer thereof is used. It is suitable to mix about 50% by weight. Further, as the tackifier, an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, an aromatic hydrocarbon resin,
Polyterpene-based resins, rosins and the like are used, and it is appropriate to mix these tackifiers in an amount of about 5 to 30% by weight.

The thickness of the hot melt type resin adhesive layer 4 is preferably about 50 to 750 μm, and 50 μm.
If it is less than m, the adhesive strength may be reduced, while on the other hand, 7
Even if it is thicker than 50 μm, the adhesive strength corresponding to it is not improved and the adhesive is wasted. The more preferable thickness of the hot melt type resin adhesive layer 4 is about 80 to 250 μm.

The synthetic resin laminate having such a structure is easily manufactured by the following method, for example. That is, between the lower mold and the upper mold of the hot press machine, a lower plate of a polycarbonate resin, a film of a hot-melt resin adhesive, an intermediate film of a thermoplastic resin, and a film of a hot-melt resin adhesive, , Acrylic resin top plate is stacked and set in sequence, the bottom plate is 90 ~ 140 ℃, the top plate is 70 ~ 110
It can be easily manufactured by a method of heating to 0 ° C., melting the film of the resin adhesive with the heat and pressing. When the heating temperature of the lower plate and the upper plate is adjusted and pressed in this way, there is an advantage that a synthetic resin laminated plate excellent in flatness with little warpage and distortion can be manufactured.

The above-mentioned synthetic resin laminated plate is a composite plate having excellent transparency and having excellent physical properties of the lower plate layer 1 of the polycarbonate resin and the upper plate layer 2 of the acrylic resin, and has high penetration resistance. It is excellent in safety and has good scratch resistance and oil resistance. In addition, this synthetic resin laminate is provided with the intermediate film layer 3 of thermoplastic resin between the lower plate layer 1 of the polycarbonate resin and the upper plate layer 2 of the acrylic resin, and the above-mentioned EVA or saponified EVA-based adhesive is mainly used. Since the lower plate layer 1, the intermediate film layer 3 and the upper plate layer 2 are bonded and integrated via the hot melt type resin adhesive layer 4 having excellent properties, the lower plate layer 1 and the upper plate layer 2 are formed. The resin adhesive layer 4
The impact strength is significantly improved as compared with the case where they are bonded and integrated with each other, and the impact resistance and the adhesive strength are the same as those of the conventional synthetic resin laminate using a polyurethane adhesive. In addition, a hot melt type resin adhesive containing EVA or saponified EVA as a main component is available at a considerably lower cost than conventional polyurethane adhesives, and an intermediate film of a thermoplastic resin is also inexpensive. The synthetic resin laminated board can reduce the manufacturing cost.

FIG. 2 is a sectional view of a synthetic resin laminated plate according to another embodiment of the present invention.

In this synthetic resin laminated plate, two intermediate film layers 3 of thermoplastic resin are provided between a lower plate layer 1 of a polycarbonate resin and an upper plate layer 2 of an acrylic resin, and these are laminated by a hot melt type resin. It is integrally bonded through the agent layer 4. The lower plate layer 1, the upper plate layer 2, the intermediate film layer 3, and the resin adhesive layer 4 are the same as those used for the synthetic resin laminated plate of FIG.

Such a synthetic resin laminate also has the same excellent physical properties as the synthetic resin laminate of FIG. 1 and has an adhesive strength and impact strength comparable to those of conventional synthetic resin laminates using a polyurethane adhesive. Have.

In the synthetic resin laminate shown in FIG. 2, two intermediate film layers 3 are provided, but three or more intermediate film layers 3 may be provided.

Next, a more specific embodiment of the present invention will be described.

[Example 1] Between a lower mold and an upper mold of a hot press machine, a lower plate of PC having a thickness of 8 mm and a hot-melt type resin adhesive having a thickness of 600 μm and containing saponified EVA as a main component were prepared. Film and biaxially stretched PET with a thickness of 75 μm
The intermediate film, the film of the hot melt resin adhesive having a thickness of 150 μm, and the PMMA having a thickness of 3 mm were sequentially stacked and set. And lower plate at about 100 ℃
300 mm in length and 300 mm in width by heating the upper plate to about 110 ° C., pressing the film of the hot-melt type resin adhesive while melting it with the heat to integrate it, and then rapidly cooling and adhering. To obtain a transparent synthetic resin laminate.

When the warpage of the synthetic resin laminated plate along the center line was measured, the warpage rate was 0.33% as shown in Table 1 below.

The total light transmittance and the haze value of this synthetic resin laminate were measured with a haze meter HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.). The light transmittance was 87.6% and the haze value was 1.1%.

Further, the PMMA upper plate layer of the synthetic resin laminated plate is placed on the upper side, both ends of the laminated plate are clamped, and a weight having a weight of 20.4 kgf is dropped onto the laminated plate from a height of 4 m. The impact resistance test was performed by applying an impact energy of about 0.8 kJ. As a result, as shown in Table 1 below, ◯ (a synthetic resin laminated plate has cracks in the PMMA upper plate but no cracks in the PC lower plate), and has excellent impact resistance (penetration resistance). Sex).

As shown in FIG. 3, the synthetic resin laminated plate is alternately staggered from the top and bottom with saw tooth grooves 5a and 5b (a saw tooth groove 5a reaching the lower plate layer 1 from the upper surface and a saw tooth groove reaching the upper plate layer 2 from the lower surface). 5b) is formed at an interval of 10 mm, and the synthetic resin laminate is pulled to both sides at a speed of 5 mm / min to measure the tensile force required to peel off the lower plate layer 1 and the upper plate layer 2. The adhesive strength was examined. As a result, as shown in Table 1 below, the adhesive strength (tensile force) was 3.95 MPa.
Met.

[Example 2] The thickness of the film of the hot-melt type resin adhesive interposed between the lower plate of PC and the intermediate film of PET was changed to 150 μm, and the upper plate of PMMA and the intermediate film of PET were changed. 300 mm in length and 300 in width in the same manner as in Example 1 except that the thickness of the film of the hot-melt type resin adhesive interposed between the layers is changed to 600 μm.
A mm transparent synthetic resin laminate was prepared. Then, with respect to this synthetic resin laminated plate, the warpage rate, total light transmittance, haze value, impact strength, and adhesive strength were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[Example 3] The same procedure as in Example 1 was repeated except that the thickness of the PET intermediate film was changed to 188 μm.
A transparent synthetic resin laminate having a length of 300 mm and a width of 300 mm was produced. Then, with respect to this synthetic resin laminated plate, the warpage rate, total light transmittance, haze value, impact strength, and adhesive strength were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[Example 4] The thickness of the film of the hot-melt type resin adhesive interposed between the lower plate of PC and the intermediate film of PET, and between the upper plate of PMMA and the intermediate film of PET. A length of 300 mm and a width of 300 are obtained in the same manner as in Example 1 except that the thickness of the film of the hot-melt resin adhesive to be interposed is changed to 100 μm.
A mm transparent synthetic resin laminate was prepared. Then, with respect to this synthetic resin laminated plate, the warpage rate, total light transmittance, haze value, impact strength, and adhesive strength were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[Embodiment 5] A lower plate of a PC having a thickness of 8 mm and a thickness of 100 μm are provided between the lower mold and the upper mold of the hot press machine.
A film of hot-melt type resin adhesive with a thickness of 75μ
m PET intermediate film, 100 μm thick hot melt resin adhesive film, and 75 μm thick PE
An intermediate film of T, a film of a hot-melt type resin adhesive having a thickness of 100 μm, and a PMMA having a thickness of 3 mm,
A transparent synthetic resin laminate having a length of 300 mm and a width of 300 mm was produced in the same manner as in Example 1 except that the layers were stacked and set in this order. Then, with respect to this synthetic resin laminated plate, the warpage rate, total light transmittance, haze value, impact strength, and adhesive strength were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[Comparative Example 1] A lower plate of PC having a thickness of 8 mm and a thickness of 900 μm were provided between the lower mold and the upper mold of the hot press machine.
In the same manner as in Example 1 except that the hot-melt resin adhesive film (1) used in Example 1 and the PMMA upper plate having a thickness of 3 mm were sequentially stacked and set. Vertical 300 mm, horizontal 300
A mm transparent synthetic resin laminate was prepared. Then, with respect to this synthetic resin laminated plate, the warpage rate, total light transmittance, haze value, impact strength, and adhesive strength were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[Comparative Example 2] A lower plate of a PC having a thickness of 8 mm and a thickness of 750 μm were provided between the lower mold and the upper mold of the hot press machine.
Polyurethane adhesive film and P of 3mm thickness
A transparent synthetic resin laminate having a length of 300 mm and a width of 300 mm was produced in the same manner as in Example 1 except that the upper plate of the MMA was sequentially stacked and set. Then, with respect to this synthetic resin laminate, the impact strength and the adhesive strength were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[0038]

[Table 1]

From Table 1, the synthetic resin laminates of Examples 1 to 5 and the synthetic resin laminate of Comparative Example 1 all had a total light transmittance of 87% to 88% and a haze value of 0. 7
Within the range of up to 1.5%, the transparency and transparency are good. Particularly, Examples 1 to 5 in which a thin hot-melt resin adhesive film and a PET intermediate film were used together for adhesion.
The synthetic resin laminate of Example 1 has a smaller haze value and is superior in transparency than the synthetic resin laminate of Comparative Example 1 in which a thick film of a hot-melt resin adhesive is used alone for adhesion. ~ 5 thick PET of 188μm
The synthetic resin laminates of Examples 1, 2, 4, 5 using the thin PET intermediate film of 75 μm have smaller haze values than the synthetic resin laminate of Example 3 using the intermediate film. From this, in order to improve transparency and transparency, it is considered advantageous to use a thin film of a hot-melt resin adhesive together with a thin PET intermediate film.

In each of the synthetic resin laminates of Examples 1 to 5 and the synthetic resin laminate of Comparative Example 1, the lower plate of PC and the upper plate of PMMA were heated at different temperatures and pressed, so that warpage occurred. And distortion is unlikely to occur, and the warpage rate is 0 to 0.33%
And few. In particular, the warp rate of the synthetic resin laminate of Example 5 using two PET intermediate films was 0%, so that increasing the number of PET intermediate films laminated is advantageous for preventing warpage and distortion. Is considered to be.

Further, the synthetic resin laminate of Comparative Example 1 adhered by using the thick film of the hot melt type resin adhesive alone does not have sufficient impact resistance, and the impact force of the dropped weight causes it to fall under the PC. Example 1 in which a hot melt type adhesive and an intermediate film of PET were used in combination while the plate layer was cracked
Each of the synthetic resin laminates Nos. 5 to 5 has the same impact strength as the synthetic resin laminate of Comparative Example 2 in which the polyurethane adhesive film is used alone, and therefore cracks are not generated in the lower plate layer of the PC. Instead, it simply deformed. From this, it is understood that the combined use of the PET intermediate film is extremely effective in improving the impact resistance.

Further, in the synthetic resin laminates of Examples 1 to 4 in which the hot melt resin adhesive film and one PET intermediate film were used together, the hot melt resin adhesive film was used alone. The adhesive strength is greater than that of the synthetic resin laminate of Comparative Example 1 bonded by the above method, and is as high as or higher than that of the synthetic resin laminate of Comparative Example 2 in which a conventional polyurethane adhesive film is used alone. In particular, a synthetic resin laminate of Example 4 in which a thin (100 μm) adhesive film and a thin (75 μm) PET intermediate film are used together, or a thin adhesive film and a thin PET intermediate film are provided in multiple layers. The adhesive strength of the synthetic resin laminate of Example 5 is remarkably improved. From these facts, it is effective to use the PET intermediate film in combination with the hot-melt resin adhesive film in order to increase the adhesive strength, especially when the thin PET intermediate film and the thin adhesive film are used in combination. Is more effective, and is extremely effective when both films are laminated in multiple layers.

[0043]

As is clear from the above description, the synthetic resin laminate of the present invention has the same impact strength and adhesive strength as those of conventional synthetic resin laminates using a polyurethane adhesive and is transparent. It is a laminated board with good safety and high penetration resistance and excellent safety, good scratch resistance and oil resistance, and can be manufactured at a lower cost than synthetic resin laminated boards using expensive polyurethane adhesives. Produce an effect.

[Brief description of drawings]

FIG. 1 is a sectional view of a synthetic resin laminate according to an embodiment of the present invention.

FIG. 2 is a sectional view of a synthetic resin laminated plate according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of an adhesive strength test conducted on the synthetic resin laminate of the present invention.

[Explanation of symbols]

1 Lower plate layer of polycarbonate resin 2 Top plate layer of acrylic resin 3 Thermoplastic resin intermediate film layer 4 Hot melt type resin adhesive layer

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F100 AK01B AK25C AK41 AK45A                       AK68D AK68G AK69D AK69G                       BA03 BA05 BA10A BA10C                       CB03 EJ202 EJ38 EJ422                       GB15 JB16B JK10 JL12D                       JN01

Claims (2)

[Claims] 1. An ethylene-vinyl acetate copolymer and / or a saponified ethylene-vinyl acetate copolymer comprising a polycarbonate resin lower plate layer, a thermoplastic resin intermediate film layer, and an acrylic resin upper plate layer. A transparent synthetic resin laminate, which is integrally bonded via a hot-melt type resin adhesive layer containing as a main component. 2. The synthetic resin laminate according to claim 1, wherein a plurality of the intermediate film layers are provided via the resin adhesive layer.