JP3489972B2 - Laminated board - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated board, and more particularly to a laminated board composed of a polycarbonate resin and an acrylic resin.

[0002]

2. Description of the Related Art Polycarbonate resin has excellent impact resistance and transparency, so its plate-like material is used for carports, signboards, etc., as well as for building glazing materials for public facilities, sports facilities, etc. It is used as a glazing material for various vehicles and as a soundproof wall for highways, and its applications are expected to expand in the future.

However, since polycarbonate resin is not sufficiently weather resistant as compared with acrylic resin and the like, when used for outdoor applications exposed to direct sunlight or the like, the impact strength is reduced and the yellow color is improved. Has been pointed out as. Various methods for improving these points have been proposed. For example, a) a method of coating a polycarbonate substrate with an acrylic resin layer containing an ultraviolet absorber (Japanese Patent Publication No. 47-19119).
Japanese Patent Laid-Open No. 55-59929), b) By using an acrylic resin having impact resistance, for example, an acrylic resin mixed with a multi-layered acrylic rubber, as an acrylic resin for coating a polycarbonate substrate. A method of imparting flexibility and impact resistance to a coating layer made of an acrylic resin (Japanese Patent Laid-Open No. 2-175245,
JP-A-4-270652) and the like.

[0004]

[Problems to be Solved by the Invention] However, the above a)
Although the weather resistance is improved by this method, there is a problem in that the impact strength of the laminated plate in which the polycarbonate resin substrate is coated with the acrylic resin is lowered. This phenomenon is that when a shock is applied, the hard acrylic resin layer breaks first,
It is presumed that the polycarbonate layer, which is firmly adhered to the acrylic resin layer, then also fractures without exhibiting its characteristics. Further, in the method of b), although the problem of lowering the impact strength is improved, the surface hardness of the acrylic resin layer is lowered due to the mixing of the rubber component, which causes a problem of being easily scratched.

Therefore, it is an object of the present invention to solve the above problems and provide a plate-like material which can be used as a glazing material, a soundproof wall or the like.

[0006]

[Means for Solving the Problem] In order to solve such a problem, the present inventors have paid attention to the following points. (1) Glazing materials for buildings and vehicles are easily soiled on the side facing the outdoors and require regular cleaning, so if the surface hardness is low, scratches are likely to occur when cleaning with a brush or the like. Further, the soundproof wall of a highway or the like is particularly liable to be soiled on the side facing the road due to the splashing of mud from a vehicle or the like, and in this case, the situation is similar to that of the glazing material. That is,
In either case, it is not necessary for both surfaces to have a high surface hardness, as long as one surface satisfies the required performance, the other surface may be usable with a lower surface hardness. (2) In the case of glazing materials such as buildings and vehicles, impact strength against flying objects mainly from the outside is required to some extent, and in the case of soundproof walls, flying objects mainly on the side facing the road are required. Impact strength is required. When an impact is applied, it is generally said that tensile stress is generated on the side opposite to the impacted side, leading to destruction from the opposite side. That is, in the case of glazing material, the side facing indoors against the impact from the outside, and in the case of noise barriers on highways, the side not facing the road from the side facing the road. , It is possible to prevent damage if there is a device that can relax the tensile stress, and it is not necessary to have high impact resistance on both sides.

As described above, in the case of glazing materials for buildings, vehicles, etc., and soundproof walls for expressways, etc., one surface is required to have high surface hardness, and the other surface is subject to impacts by flying objects. At least impact strength that can withstand the tensile stress that acts upon receiving is required.

The inventors of the present invention have made extensive studies in consideration of the above points, and as a result,
The present invention has been completed by finding that a laminated board co-extruded so as to have acrylic resin layers having different impact resistances and different flexibility can solve such problems.

That is, according to the present invention, the above object is
On one surface of the polycarbonate resin layer has an acrylic resin layer having a meta acrylic resin containing less than UV absorber 0.1-2 wt% and crosslinked acrylate polymer 30% by weight of (A), the laminate having the other of the acrylic resin layer having a meta acrylic-based resin containing 0.1 to 2 wt% and 30 to 70 wt% crosslinked acrylic ester polymer ultraviolet absorber on the surface of (B) Can be achieved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The polycarbonate resin constituting the polycarbonate resin layer, which is the substrate layer in the present invention, includes
There is no particular limitation, and for example, a carbonic acid ester polymer mainly containing bisphenol A is used. The method for producing the polycarbonate resin is not particularly limited, and those produced by known methods such as the phosgene method and the transesterification method can be used. The molecular weight is not particularly limited either, but since it is produced by extrusion molding, it has a viscosity average molecular weight of about 15,000 to 30,000, or a melt viscosity at 250 ° C. and 100 s ⁻¹ of 13,000.
Those having a poise of about 60,000 poise are preferably used. The thickness of the polycarbonate resin layer is not particularly limited,
It is usually 1 to 20 mm, preferably 2 to 10 mm. The polycarbonate resin layer may contain various commonly used additives, and examples of the additives include an ultraviolet absorber, an antioxidant, a flame retardant, and a colorant.

The methacryl resin, which is one of the resin components constituting the acrylic resin layer (A) and the acrylic resin layer (B) that are the coating layers in the present invention, is a homopolymer of methyl methacrylate or a methyl methacrylate unit. Copolymers containing 50% by weight or more, preferably 85% by weight or more, and those capable of extrusion molding are preferably used. Examples of the monomer copolymerizable with methyl methacrylate include methyl acrylate, ethyl acrylate, and butyl acrylate. These can be used alone or in combination of two or more. Methacrylic resin is 250 ℃, 100s from the viewpoint of moldability.
Those having a melt viscosity of about 5,000 to 31,000 poise at ^-1 are preferably used. The method for producing the methacrylic resin is not particularly limited, and known methods such as bulk polymerization, suspension polymerization, solution polymerization and emulsion polymerization can be adopted. Various commonly used additives may be added to the methacrylic resin, and examples thereof include antioxidants, flame retardants, and colorants.

In the present invention, the crosslinked acrylic acid ester-based polymer, which may be or may be contained in the methacrylic resin, is a rubber component compounded for improving the impact strength of the laminate. The crosslinked acrylate polymer is not particularly limited as long as it does not impair the object of the present invention, and those having various layer structures can be used. For example, a hard methacrylic polymer and a rubber can be used. Examples thereof include those having a two-layer structure, a three-layer structure, and a four-layer structure in which a soft cross-linked polymer having an acrylic acid ester as a main component and having a similar property is layered. The crosslinked acrylic acid ester-based polymer usually has a spherical shape composed of two or more layers and has an average particle size of 0.1 to 0.3 μm.
The thing of about m can be used preferably.

The crosslinked acrylic acid ester-based polymer is an impact-resistant multi-layered methacrylic resin containing a rubber component of the crosslinked acrylic acid ester-based polymer having various layer structures from the viewpoint of melt-mixability with the methacrylic resin. Is preferably used. For example, 70 to 90% by weight of at least one kind of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group
And styrene alone or a mixture of styrene and its derivatives 9.9 to 29.9% by weight and copolymerizable therewith 1
A crosslinked acrylic acid ester-based polymer latex obtained by using 0.1 to 10% by weight of a polyfunctional monomer having two or more double bonds in the molecule, such as allyl acrylate and allyl methacrylate, or Outside the hard crosslinked resin particles containing 80% by weight or more of methyl methacrylate unit, 70 to 90% by weight of at least one alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and styrene alone or a mixture of styrene and a derivative thereof. 9 to 29.9% by weight and 0.1 to 10% by weight of a multifunctional monomer such as allyl acrylate or allyl methacrylate having two or more double bonds in one molecule which is copolymerizable therewith.
80% to 100% by weight of methyl methacrylate and 1 to 8 carbon atoms of the alkyl group in the presence of a crosslinked acrylic acid ester-based polymer latex having a polymer layer obtained by using
At least one of alkyl acrylates of 0 to 2
It can be obtained by emulsion polymerization of a monomer mixture consisting of 0% by weight and 0 to 10% by weight of another vinyl monomer copolymerizable therewith. In the above-mentioned production method, by increasing the quantitative ratio of the methacrylic resin component in the outermost layer, it is possible to produce a multilayer structure containing the crosslinked acrylic acid ester polymer in one step.

As a method for producing a multi-layer structure, an emulsion polymerization method in which a monomer mixture constituting each layer is sequentially polymerized from an inner layer is usually used. The addition method of the monomer mixture, selection of an emulsifier, Whether or not a chain transfer agent is added to the outermost layer is not particularly limited. Further, the ratio of the crosslinked acrylic acid ester-based polymer in the methacrylic resin having a multilayer structure is 2
It is desirable to set it to about 0 to 70% by weight.

The ultraviolet absorber used in the present invention is used for the purpose of improving the weather resistance of the laminated plate, and the kind thereof is not particularly limited, and for example, known benzosotriazole type, hindered amine type, benzophenone type, etc. One kind or two or more kinds selected from ultraviolet absorbers are used. The amount of the ultraviolet absorber added is 0.1 to 2% by weight, preferably 0.5 to 1.5, based on the total amount of the acrylic resin layer.
% By weight. If the addition amount is less than 0.1% by weight, the weather resistance that can withstand outdoor use cannot be obtained, which is not preferable.
On the other hand, even if the addition amount exceeds 2% by weight, it is hard to say that the effect corresponding to the addition cost is obtained, and conversely, the excessive addition amount causes slipping in the extruder or contamination of the forming roll with volatile matter. This may cause adverse effects and is not preferable.

The acrylic resin layer (A) formed on one surface of the polycarbonate resin layer in the laminate of the present invention is
0.1 to 2% by weight of an ultraviolet absorber and less than 30% by weight of a crosslinked acrylate polymer, preferably 0 to 2
It is formed from a methacrylic resin containing 0% by weight, more preferably 10 to 20% by weight, and its main purpose is to improve the surface hardness and weather resistance of the polycarbonate resin layer. The surface hardness of the polycarbonate resin plate is usually 2B in pencil hardness.
On the other hand, the acrylic resin layer (A) has a rubber component content of less than 30% by weight, which is a factor for lowering the surface hardness, while the acrylic resin layer (A) has a low surface hardness. A surface hardness of 2H to 3H can be maintained. Further, by containing a small amount of a cross-linked acrylic acid ester-based polymer which is a rubber component, it is possible to impart appropriate impact resistance.

The acrylic resin layer (B) formed on the other surface of the polycarbonate resin substrate in the laminate of the present invention comprises 0.1 to 2% by weight of an ultraviolet absorber and a crosslinked acrylate polymer. 30-70% by weight, preferably should be formed from meta acrylic-based resin containing 30 to 50 wt%. When the content of the crosslinked acrylic acid ester-based polymer is less than 30% by weight, flexibility that does not impair the impact strength of the polycarbonate resin substrate,
It is difficult to impart impact strength, while when it exceeds 70% by weight, the flowability of the acrylic resin becomes poor, which is not preferable in melt extrusion molding.

Although it is possible to make the acrylic resin layers formed on both sides of the polycarbonate resin layer the same component, the amount of the rubber component contained in the acrylic resin layer is reduced in order to improve weather resistance and surface hardness. As a result, a crack is likely to be formed on the side to which tensile stress is applied due to deformation from one side, a notch is generated when an impact is applied, and the impact strength of the laminated plate is reduced. On the other hand, if the amount of the rubber component contained in the acrylic resin layer is increased in order to maintain the impact resistance of the laminated plate at the same level as that of the polycarbonate resin, the surface hardness will decrease. In any case, the object of the present invention cannot be achieved.

In the laminated board of the present invention, since the addition amount of the multi-layered granular elastic material contained in the acrylic resin layer formed on the polycarbonate resin substrate is changed, the one side has a surface hardness and a weather resistance on the polycarbonate resin substrate. The other surface can give impact resistance to the polycarbonate resin substrate.

Since the laminated plate of the present invention has the above characteristics, the direction of use may be limited depending on the intended use. For example, when the laminated plate of the present invention is used as a soundproof wall for a highway or the like, when a vehicle or flying object collides with it, a large tensile stress is generated on the surface opposite to the road, and it is repelled from the vehicle or the like. It is preferable to use the acrylic resin layer (B) side on the side opposite to the road because dirt such as mud adheres significantly to the side of the soundproof wall facing the road and the frequency of cleaning increases. When using the laminated plate of the present invention as a glazing material for buildings and various vehicles,
Since it is the side facing the outdoors that dirt and dust due to sand or dust are likely to occur, it is preferable to use the acrylic resin layer (B) side for the interior side.

The thickness of the acrylic resin layers (A) and (B) formed on both surfaces of the polycarbonate resin layer is
There is no particular limitation, but from the viewpoint of weather resistance, etc., 2
It is desirable to be in the range of 0 to 150 μm, preferably 50 to 100 μm.

The method for producing the laminated plate of the present invention includes:
The method is not particularly limited, and a casting method, compression molding, extrusion molding and the like can be adopted, but extrusion molding, particularly coextrusion molding is preferable from the viewpoint of mass productivity, moldability and the like. As an extruder used for manufacturing a laminated plate, generally, a main extruder that extrudes a polycarbonate resin that forms a substrate layer, a sub-extruder 1 that extrudes an acrylic resin (A) that forms a coating layer, and an acrylic type It is composed of a sub-extruder 2 for extruding the resin layer (B), and as the sub-extruders 1 and 2, those smaller than the main extruder are usually used. As the stacking method, a known method such as a feed block method or a multi-manifold method can be adopted.

In the case of the feed block system, the resin to be laminated is guided to a sheet forming die such as a T die and formed into a laminated sheet, and then flows into a forming roll (polishing roll) whose surface is mirror-finished. Then, after forming the bank, it is mirror-finished while passing through the forming roll and cooled to be a laminated plate having an excellent appearance. In the case of the multi-manifold method, the molten resin is molded into a laminated sheet inside the die, and then surface finishing and cooling are performed with a molding roll,
It becomes a laminated board with an excellent appearance. The total thickness of the laminated plate can be adjusted by the roll gap, and the thickness ratio of each layer can be controlled by the ratio of the extrusion amount of each extruder. The thus obtained laminate has a thickness of usually 1 to 25 mm, preferably 3 to 15 mm. The obtained laminated plate can be used as it is as a flat plate, or can be used by being secondarily formed and processed into a curved shape.

[0025]

The present invention will be described in more detail with reference to examples. The evaluation / measurement methods of the examples were carried out by the following methods.

(Evaluation of Impact Resistance) Using a graphic impact tester (manufactured by Toyo Seiki Co., Ltd.), a falling weight impact test was conducted three times under the following conditions, and the maximum load at breakage was determined by measuring under the following conditions. . Test conditions: Weight weight; 6.5 kg, drop height; 15
0 cm, sample time; 5 μsec. , Room temperature 23 ℃ / 5
0% RH Specimen size: 100 mm × 100 mm × 2 mm Thickness falling weight: striker curvature; 13 mm, clamp diameter; 75 m
mφ

(Measurement of Surface Hardness) Pencil hardness was measured using a scratch tester (JIS-K5401) according to JIS-K5400.

The following resins and ultraviolet absorbers were used in the examples. (Polycarbonate resin) TAFRON I2200 (manufactured by Idemitsu Petrochemical Co., Ltd.)

As the resin composition of the acrylic resin layer, the following methacrylic resin and multi-layered methacrylic resin having the ratios shown in Table 1 were used. (Methacrylic resin) consisting of 94% by weight of methyl methacrylate unit and 6% by weight of methyl acrylate unit,
A methacrylic resin having a weight average molecular weight of 160000 was used.

(Multilayer Methacrylic Resin) A three-layer polymer latex obtained by the following three-step polymerization is frozen,
A powder containing 60% by weight of a crosslinked acrylic acid ester-based polymer obtained by melting and drying was used. (First stage) Ion-exchanged water 3 in a reaction vessel equipped with a reflux condenser
00 parts by weight, 1 part by weight of sodium stearate and 0.08 part by weight of sodium N-lauroyl sarcosinate were added, and the temperature was raised to 70 ° C. under a nitrogen atmosphere with stirring, and then methyl methacrylate (MMA) 23.25. Parts by weight, methyl acrylate (MA) 2 parts by weight, allyl methacrylate (A
A monomer mixture consisting of 0.15 parts by weight of LMA) was added. Then, a 10% potassium persulfate (KPS) aqueous solution of 0.
3 parts by weight was added, the temperature was raised to 80 ° C., and the temperature was maintained for 60 minutes. (Second step) In the presence of the latex obtained in the first step, 0.3 part by weight of a 10% KPS aqueous solution was added, followed by 28 parts by weight of butyl acrylate, 5.8 parts by weight of styrene, and AL.
A monomer mixture consisting of 0.8 part by weight of MA was continuously added over 60 minutes and kept for 30 minutes after the addition was completed. (Third step) Next, in the presence of the latex obtained in the second step, 0.4 part by weight of a 10% KPS aqueous solution was added,
A monomer mixture consisting of 39 parts by weight of MMA, 1 part by weight of MA, and 0.07 parts by weight of n-octyl mercaptan was continuously added over 40 minutes, and the mixture was kept for 60 minutes after the addition was completed.
A layered polymer latex was obtained.

(Ultraviolet absorbent) ADEKA SUDAB LA-31 (manufactured by Asahi Denka Kogyo: benzotriazole type)

(Examples 1 and 2, Comparative Examples 1 and 2) Polycarbonate resin was fed from the main extruder (φ50 mm single-screw extruder) at 30 kg / hr and the sub-extruder 1 (φ30).
2 mm / hr of the acrylic resin layer A shown in Table 1 containing 0.5% of an ultraviolet absorber, and ultraviolet rays from the other sub-extruder 2 (φ30 mm single-screw extruder). Each of the acrylic resin layers B shown in Table 1 containing 0.5% of an absorbent was melt-extruded, and these three layers were joined in a multi-manifold die for co-extrusion having a die width of 400 mm to form a laminated sheet. After that, the laminated resin discharged from the die was passed through a cooling roll adjusted so that the total thickness of the laminated plate was 2 mm, cooled and mirror-finished to manufacture a laminated plate. Also in this laminated plate, the thickness of the acrylic resin layer was 100 μm. The resulting laminated plate was subjected to a falling weight impact test and pencil hardness measurement of the acrylic resin layer (A) surface, and the results are shown in Table 2.

(Comparative Example 3) A polycarbonate resin of φ5 was used.
By extruding from a 0 mm single screw extruder, forming a sheet with a die for a single layer sheet having a die width of 400 mm, and passing through a cooling roll adjusted to have a plate thickness of 2 mm,
After cooling and mirror finishing, a single-layer polycarbonate resin plate having a thickness of 2 mm was obtained. The resin plate thus obtained was subjected to a falling weight impact test and a pencil hardness measurement, and the results are shown in Table 2. It can be seen from Table 2 that the laminated board of the present invention has impact strength comparable to that of the polycarbonate resin single layer board and surface hardness of the acrylic resin.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

INDUSTRIAL APPLICABILITY As described above, the laminated plate of the present invention is excellent in scratch resistance while maintaining the impact strength of the polycarbonate resin, so that it can be used as a glazing material for public facilities, exercise facilities and various vehicles. It is suitable as a glazing material, a soundproof wall for expressways, etc.

Front page continuation (72) Minor Ishiyama Minoru No. 2-28 Kurashiki-cho, Nakajo-cho, Kitakanbara-gun, Niigata Prefecture Kuraray Co., Ltd. (56) Reference JP-A-7-223298 (JP, A) (58) Fields investigated (58) Int.Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (4)

(57) [Claims] 1. A polycarbonate resin layer on one surface,
Acrylic resin layer having a meta acrylic resin containing an ultraviolet absorber less than 0.1 to 2 wt.% And a crosslinked acrylic ester polymer 30 wt% has a (A), an ultraviolet absorber on the other surface laminate, characterized in that it comprises an acrylic resin layer having a meta chestnut <br/> Le resin containing 0.1 to 2 wt% and 30 to 70 wt% crosslinked acrylic ester polymer (B) Board. 2. The laminate according to claim 1, which is obtained by coextrusion molding. 3. A glazing material comprising the laminated plate according to claim 1. 4. A soundproof wall made of the laminated plate according to claim 1.