JPS6260244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a synthetic resin laminate having a polycarbonate resin surface layer, and in particular, by applying an ultraviolet curable primer to a polycarbonate resin sheet or film and using this. The present invention relates to a method of manufacturing a synthetic resin laminate by cast molding.

Polycarbonate resin (hereinafter referred to as PC)
Synthetic resin laminates having a layer on the surface are known, for example, as disclosed in Jitsukasho, filed by one of the present applicants.
It is described in Publication No. 53-62880 and Japanese Patent Application Laid-Open No. 55-49261. Synthetic resin laminates having a PC surface layer have many uses as plates with high impact resistance. Regarding this synthetic resin laminate body having a PC surface layer, the present inventors have considered increasing the thickness of the PC layer, adding an uneven pattern to the surface, and obtaining a transparent synthetic resin laminate body. . It is difficult to manufacture these by the method described in the above-mentioned Japanese Patent Application Laid-Open No. 55-49261. The first reason is
Since the method described in the above publication requires the use of a pre-laminated film using a thin PC film, it is not possible to use a thick PC sheet, and furthermore, it is difficult to use a thin PC film with an uneven pattern. I can't. The second reason is that heat and pressure are used to laminate the pre-laminated film and the vinyl chloride resin sheet.
It is almost impossible to use a PC sheet that has an uneven pattern on its surface. The third problem is that the hot melt type adhesives used are not sufficiently transparent, and the fourth problem is that when heating and pressing thick laminates, each synthetic resin constituent layer is uniformly coated. However, it is difficult to heat it sufficiently.

The present inventor further investigated adhesives that can firmly bond PC and other synthetic resins. In general, PC has poor solvent resistance, and if adhesives containing solvents or highly soluble liquid monomers are used, the surface will be attacked in a short period of time, easily causing cracks and whitening. On the other hand, the so-called dope bonding method takes advantage of the solubility of PC and uses an adhesive dissolved in a solvent such as methylene chloride.
Although it is effective for adhering PC boards to each other, it has poor adhesion to different types of synthetic resins, making it impractical. Additionally, when bonding a PC board with a large area, or a PC board and a different type of synthetic resin board, non-reactive solvents such as dope adhesive may be encapsulated in the adhesive layer, which may adversely affect adhesive strength and other properties. unfavorable to Furthermore, as mentioned above, the use of hot melt adhesives is not suitable for the present purpose due to the necessity of heating and pressurizing.

In order to produce a thick laminate, the present inventor uses at least one PC sheet or film (hereinafter referred to as a sheet including other structures, but excludes films unless otherwise specified). We studied a method of manufacturing a laminate that integrates this cured material with a PC sheet by filling a liquid curable synthetic resin raw material between the PC sheet and another sheet and curing the material. In this case, two PC sheets are used, and a liquid curable synthetic resin raw material is filled between the two PC sheets and cured to obtain a laminate having both surfaces made of PC. As will be described later, this molding method is hereinafter referred to as cast molding. What is important in this manufacturing method is that the PC surface layer and the cured synthetic resin layer are firmly adhered to each other. Liquid curable synthetic resin raw materials have high adhesive properties that can be used as adhesives in many cases. However, as with the doped adhesives above, this tends to dissolve the PC surface and therefore has the same problems as above. Moreover, since a much larger amount of liquid curable synthetic resin raw material is used than when used as an adhesive to form a thick synthetic resin layer, the PC
The erosion of the layers is so severe that it is impossible to bring them into contact.

Therefore, the present inventor considered applying a primer to the surface of the PC layer to solve this problem. First, this primer must be capable of strongly adhering the PC layer and the cured synthetic resin layer.
Second, the primer must protect the PC surface from the liquid curable synthetic resin raw material and be difficult to dissolve in the liquid synthetic resin raw material. Furthermore,
Third, the primer itself must be resistant to attack the PC surface. Moreover, in order to produce a transparent laminate, the primer must have high transparency. As a result of researching and considering various primers that can satisfy these requirements, the present inventors have discovered an ultraviolet curable primer that has less potential to dissolve PC. By using this primer, the present inventor was able to produce an excellent laminate having a PC layer on the surface. The present invention relates to a method for manufacturing this laminate, that is, a method for manufacturing a synthetic resin laminate having a polycarbonate resin surface layer on at least one side, in which an ultraviolet curable resin is coated on one side of a polycarbonate resin sheet or film. A primer is applied, the primer is partially cured without being completely cured by irradiation with ultraviolet rays, and then a sheet or film forming another surface layer is spaced so as to face the partially cured primer layer. This is a method for producing a synthetic resin laminate, characterized in that a liquid curable synthetic resin raw material is cured between the two sheets or films.

FIGS. 1 to 4 are partial cross-sectional views showing steps of implementing an example of the method of the present invention. Figure 1 shows a cross section of a PC sheet 2 with an ultraviolet curable primer layer 1 formed on one side, and Figure 2 shows an ultraviolet lamp 3.
FIG. 3 is a cross-sectional view showing a state in which the primer is partially cured. FIG. 3 is a cross-sectional view of the casting mold, in which the PC sheet 2 forming the primer layer 1 and the sheet 4 forming the other surface layer are arranged at intervals so as to face the primer layer 1, and a gasket is placed around the periphery. 5, and a holding material 6 fixes the PC sheet 2 and the sheet 4 forming the other surface layer. The gap between the PC sheet 2 and the sheet 4 forming the other surface layer becomes a cavity 7, which is filled with a liquid curable synthetic resin raw material and cured in that state. FIG. 4 shows a synthetic resin laminate obtained by this method. In FIG. It can be obtained by removing it. FIG. 5 is a partial sectional view showing another example of a synthetic resin laminate obtained by the method of the present invention, in which both surface layers are made of PC9 and 10, and the UV-curable primer layers 11 and 12 are cured, respectively. The hardened synthetic resin layer 13
It is glued with. This laminate is shown in FIG. 3 in place of the sheet 4 forming the other surface layer.
A PC sheet 2 having a partially cured primer layer 1 obtained as shown in FIGS. Can be done. FIG. 6 is a partial cross-sectional view showing an example of still another synthetic resin laminate obtained by the method of the present invention, in which the same process as above is carried out by using folded PC sheets 14 and 15. Therefore, it can be manufactured.

The synthetic resin laminate obtained by the method of the present invention is particularly preferably a laminate in which both surface layers are PC layers, as shown in cross section in FIGS. 5 and 6. The surface of the PC layer, which is the surface of the laminate, may have molded or mechanically processed irregularities, or may have a patterned surface by printing or other means. Furthermore, a hard coat layer may be provided with paint or the like. Further, the PC layer may be a PC added with an ultraviolet absorber or the like, or colored to make it difficult to transmit ultraviolet rays. This is the second
As shown in the figure, this is because the primer layer can be partially cured by irradiating ultraviolet rays from above the surface of the ultraviolet curable primer layer.
In the case of PC, the primer layer can be partially cured by irradiating ultraviolet rays from above the PC surface.

In addition, as shown in FIG. 3, by using a material that can firmly adhere to the cured synthetic resin when the liquid curable synthetic resin hardens as the sheet 4 forming the other surface layer, one side can be made of PC. , laminates can be produced with surface layers, the other being of other materials. This material may be of course synthetic resin, metal, inorganic material such as glass, or other materials. If this material is difficult to adhere firmly to hardened synthetic resin,
Similar to PC, its surface can also be treated with various primers.

The UV-curable primer is PC as described below.
It does not contain soluble components, or even if it does, it has low PC solubility.
And the amount is small. This primer is in liquid form and can be applied to one side of the PC sheet in a variety of ways. For example, if the PC sheet is flat, it can be coated with a wire coater or bar coater, and if it is a non-flat surface, such as a curved or folded surface, it can be coated by spraying or brushing. Although the coating thickness is not particularly limited, it is preferably thin from the viewpoint of cost, and 10 to 200 μm is suitable for practical use. It is not preferable to completely cure the applied primer with ultraviolet rays because this will reduce the adhesion to the synthetic resin layer. On the other hand, if the degree of curing of the primer is too low, the primer will easily dissolve in the liquid curable synthetic resin raw material, reducing the effectiveness of protecting the PC surface, increasing the risk of the PC surface being attacked, and reducing adhesive strength. do. Therefore, it is preferable to partially cure the primer to such an extent that the surface of the primer feels somewhat sticky to the touch.

In order to irradiate ultraviolet rays to partially cure the primer, it is preferable to use a light source with a large amount of ultraviolet rays, such as a mercury lamp. The properties of the primer in terms of curability depend on the light source wavelength range, output, and irradiation time of the ultraviolet irradiation device, but for example,
High-pressure mercury lamp for photochemistry (wavelength range 245-577mm, output
When irradiated with 80 W/cm) from a height of 50 cm above the primer coated surface, it is suitable that the primer cures within 30 seconds, particularly within about 2 to 10 seconds, leaving some tackiness as described above. Of course, these conditions may vary depending on the type of primer, the type and amount of photosensitizer added, and other conditions. If you change the intensity of ultraviolet rays,
Although the irradiation time may become longer, it is not preferable to significantly lengthen the irradiation time. This is because the primer tends to attack the PC surface to some extent and cause it to whiten. Conversely, significantly shortening the curing time will reduce the reproducibility of the degree of partial curing,
Moreover, it tends to reduce adhesive strength. Therefore, in practice, it takes 30 seconds to partially cure the primer.
It is preferable to irradiate the film with ultraviolet light for 45 minutes, particularly 2 to 30 minutes, to partially cure it while leaving some tackiness.

PC is not limited to polycarbonate resins having ordinary polyphenol residues (for example, bisphenol A residues) and 〓〓〓〓 groups, but also includes polycarbonate resins having polyhydric alcohol residues, polyester carbonate resins, etc. It may be a resin consisting of a polycarbonate-based copolymer, or it may be a blend resin of these polycarbonate-based resins and other synthetic resins. In the case of a blend resin, the proportion of PC therein is preferably 20% by weight or more, particularly 60% by weight or more. PC contains ultraviolet absorbers, flame retardants, stabilizers, colorants,
Fillers and other additives can be added. Preferably, the PC is substantially transparent or translucent to visible light. "Substantially" means that it is transparent or translucent unless there are surface irregularities or patterns. In addition, from the viewpoint of weather resistance, it is preferable that the PC be one that contains an ultraviolet absorber and is difficult to transmit ultraviolet rays. Further, the thickness of the PC layer is preferably 0.5 mm or more, particularly 0.8 to 10 mm, but is not limited thereto. The reason why this is preferable is that a laminate having a thick PC layer, which is difficult to obtain by the method using film-like PC described in the above-mentioned known example, can be obtained. Of course, 0.5mm
The method of the present invention can also be applied to the case where a laminate with excellent transparency and high interlayer adhesion is obtained using a PC sheet or film having a thickness of less than 100 mL. of laminate
The PC layer is formed by using a PC sheet, and as mentioned above, the sheet includes a film. In the present invention, preferably 0.5
Use a PC sheet with a thickness of mm or more. In the present invention, the term "sheet" refers to a sheet having a thickness of 0.2 mm or more, and the term "film" refers to a sheet having a thickness less than 0.2 mm. The PC sheet is not limited to those having a flat surface as described above, but may also be a sheet having a curved surface, a molded sheet formed into various shapes, or a sheet subjected to secondary processing such as bending.

It is preferable that the UV-curable primer does not contain components that easily dissolve PC, or even if it does, the amount thereof is small. One of the easily soluble components of PC
One is a solvent. Preferably, this solvent is substantially absent from the primer. Other PC easily soluble components are monomers having polymerizable unsaturated groups such as styrene. Since this easily soluble PC monomer usually has a low boiling point, it will hereinafter be referred to as a low boiling point monomer. Examples of low-boiling monomers include styrene, P-vinyltoluene, methyl methacrylate, methyl acrylate, and vinyl acetate. The ultraviolet curable primer preferably does not contain styrene, and particularly preferably does not substantially contain a low-boiling monomer having a boiling point of about 100° C. or lower (the boiling point of methyl methacrylate). However, these low boiling point monomers
If the solubility in PC is low and the amount is small,
Even if it is contained to some extent, it can be used because it reacts and polymerizes quickly with ultraviolet rays and has little adverse effect. There are not many such UV-curable primers on the market, but for example, the UV-curable "Spiratsuku" (trade name) manufactured by Showa Kobunshi Co., Ltd. and the Nippon Gosei Kagaku Kogyo Co., Ltd. There are products such as the UV-curable "Go-Serak" (trade name). For example, the former is presumed to be a compound containing a cycloacetal compound having a polymerizable unsaturated group as a main component with a photosensitizer added (JP-A-56-2312, JP-A-53- 7796, JP-A-52-154884, etc.), and is considered to be free of solvents and low-boiling monomers such as styrene. In addition, epoxy acrylate-based, polyester acrylate-based, and other UV-curable primers may be used.

As the liquid curable synthetic resin raw material, a liquid raw material that can be cured by polymerization, polycondensation, etc. to become a synthetic resin such as a thermoplastic resin or a thermosetting resin can be used. In particular, thermosetting resins such as unsaturated polyester resins, vinyl ester resins, and epoxy resins are preferred. Furthermore, acrylic monomers such as methyl methacrylate, prepolymers thereof, and curable monomers and prepolymers capable of forming thermoplastic resins such as styrene can also be used as long as they have a relatively short curing time. These can be made to be curable at room temperature or under heating by adding a polymerization initiator. Furthermore, a photosensitizer or the like can be added to make it curable by ultraviolet rays or radiation. Preferably, a liquid thermosetting resin that can be cured at room temperature or relatively low temperature is used. The curing temperature is not particularly limited, but is approximately
Those that can be cured at 100°C or lower are preferred. Also,
The gelation time is preferably within several hours, particularly within 2 hours. This is because if the curing temperature is too high or the gelation time is too long, the primer will easily dissolve.

The partially cured primer can be cured almost simultaneously with the curing of the liquid curable synthetic resin raw material, even without irradiation with ultraviolet rays. this is,
This is because the primer can be cured at room temperature to heating, and the polymerization initiator contained in the liquid curable synthetic resin raw material may also act on the curing of the primer. If necessary, the liquid curable synthetic resin raw material can be cured while irradiating the primer with ultraviolet rays. It goes without saying that the PC surface layer can transmit ultraviolet rays, but even if it is barely permeable to ultraviolet rays, if the liquid curable synthetic resin raw material and the sheet 4 forming the other surface layer in FIG. 3 are transparent to ultraviolet rays. The liquid curable synthetic resin raw material can be cured while irradiating ultraviolet rays onto the sheet 4 forming the surface layer. Furthermore, it is also a preferable method to use an ultraviolet curable material as the liquid curable synthetic resin raw material and to similarly cure the liquid curable synthetic resin raw material and the primer while irradiating the resin with ultraviolet rays.

In addition to the polymerization initiator and photosensitizer described above, various additives and embedding materials can also be blended or placed in this liquid curable synthetic resin raw material. for example,
Additives such as flame retardants, stabilizers, colorants, reinforcing materials, and paper, cloth, nonwoven fabrics, fibers, porous boards, and other embedded materials can be used. For example, by arranging glass fiber pine, roving cloth, carbon fiber pine, etc., this hardened synthetic resin layer can be made into a fiber-reinforced synthetic resin layer, and by arranging decorative paper or decorative cloth, it can be used as a decorative layer. can do.

Although the thickness of the layer of the cured product of the liquid curable synthetic resin raw material is not particularly limited, it is preferably thick. In particular, the thickness thereof is preferably 0.5 mm or more, preferably 2 mm or more. When producing particularly thick laminates, the layer thickness should be 5 mm.
It is preferable to make it more than that. Further, the thickness of the laminate obtained by the present invention is not particularly limited, but is preferably 2 mm or more, particularly 5 mm or more.
The method of the present invention is characterized in that a particularly thick laminate can be produced, and a laminate with a thickness of 10 mm or more can be produced. As mentioned above, the laminate obtained by the present invention is not limited to a flat plate shape, but can be manufactured in various shapes such as a curved plate shape and a bent shape. Further, after manufacturing the laminate, it can be processed into various shapes by secondary processing such as cutting and cutting. Furthermore, the laminate produced according to the present invention can also be subjected to surface treatments such as surface painting, hard cord treatment, and patterning.

The laminate of the present invention can be used for various purposes. Since the laminate of the present invention has high strength, excellent weather resistance, and excellent transparency, it is suitable for, for example, door materials and window materials for buildings. For example, in the case of doors, tempered glass doors and acrylic resin doors have traditionally been used as doors with excellent transparency. However, tempered glass doors are heavy and it is not possible to add textured patterns to the surface. On the other hand, doors made of acrylic resin are lightweight and can be patterned with irregularities, but even if they contain UV absorbers, they have poor weather resistance and are prone to minute cracks on the surface. Since the door made of the laminate of the present invention has a PC layer on its surface that hardly transmits ultraviolet rays, its weather resistance is much higher than that of an acrylic resin door. On the other hand, PC doors are not only extremely expensive compared to the material they are made of, but also thick ones must be manufactured by laminating many PC sheets, which is difficult due to the nature of PC. The laminate produced according to the present invention has an inexpensive intermediate layer, and the intermediate layer and the surface PC
Not only does it have excellent adhesive strength with the layer, but it is also highly transparent to visible light, and it is easy to form uneven patterns on the surface. Furthermore, it is easy to embed decorative paper or the like in the intermediate layer, and a door material with excellent decorative properties can be easily obtained. Therefore, it has far more suitable performance than conventional door materials.

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.

Example 1 A polycarbonate resin sheet (trade name: "Lexan", sold by Asahi Glass Co., Ltd.) with a thickness of 2.2 mm and a size of 1000 x 2000 mm containing approximately 0.2% by weight of ultraviolet absorber was coated with an ultraviolet curable primer "Spirac U-3253" on one side. −
1X" (trade name, sold by Showa Kobunshi Co., Ltd.) was applied to a thickness of 50 μm using a wire coater. This primer is mainly composed of a cycloacetal compound having the above-mentioned polymerizable unsaturated group, It does not contain solvents or low-boiling monomers such as styrene. Immediately after applying the primer, a large number of copying fluorescent lamps "FL40BA-37" φ-35mm (sold by Matsushita Electric Industrial Co., Ltd.) were arranged in parallel at 30mm intervals. Ultraviolet rays were applied using an ultraviolet irradiation device set at a distance of 150 mm from the primer layer, and treatment was carried out at about 25° C. for about 15 minutes to cure the primer to the extent that the primer surface became slightly sticky.

Two polycarbonate resin sheets having the above-mentioned partially cured primer layer were manufactured, and the two sheets were placed facing each other with the primer layer inside, and a 10 mm diameter soft polyvinyl chloride resin pipe was placed around the middle of the sheets to form a gasket. , inside the formed cavity, unsaturated polyester resin
2004WM-2” (Product name, sold by Showa Kobunshi Co., Ltd.) 100
parts (by weight, the same applies hereinafter) to 1 part of accelerator "E" and 1 part of accelerator "K" (both trade names, Showa Kobunshi Co., Ltd.)
The container was filled with a well-mixed mixture of 2 parts of the polymerization initiator "Permec N" (trade name, sold by NOF Corporation). Gelation was completed by leaving it at about 25°C for about 60 minutes, and then leaving it at that temperature for about 16 hours. Next, it was heated to 80°C, held for 60 minutes, and then allowed to cool to complete curing. As a result, a completely transparent laminate having a thickness of about 14 mm was obtained, which was made of polycarbonate resin on both surfaces and hardened unsaturated polyester resin at the core. When a sharp wedge was driven between the two layers to check the adhesive strength between the surface layer and the core layer, the polycarbonate resin of the surface layer was destroyed without peeling between the two layers.

Example 2 Two polycarbonate resin sheets having partially cured primer layers manufactured in the same manner as in Example 1 were prepared, and with the primer layers facing each other, a soft polyvinyl chloride resin tube with a diameter of 8 mm was placed around the periphery as a gasket. A casting mold similar to that in Example 1 was formed by sandwiching the mixture. The cavity of this casting mold was filled with an unsaturated polyester resin having the same composition as in Example 1, and then glass fiber mat was gradually dipped and filled from the top. Clamp around the casting mold and heat to approximately 25℃.
When the unsaturated polyester resin was left to stand still in an atmosphere of about 60 minutes, gelation of the unsaturated polyester resin was completed. This was left as it was for 16 hours, further heated at 80° C. for 60 minutes, allowed to cool, and the laminate was taken out.

The obtained laminate was constructed by sandwiching FRP with a thickness of about 10 mm with a polycarbonate resin sheet, and its adhesion and weather resistance were as good as those produced in Example 1.

Example 3 A polycarbonate resin sheet having a partially cured primer layer on one side was produced in the same manner as in Example 1. Place this sheet and the glass plate facing each other so that the primer layer is on the inside, and add a diameter to the periphery.
Using a 10 mm soft polyvinyl chloride resin tube as a gasket, the formed cavity was filled with an unsaturated polyester resin having the same composition as in Example 1, and cured under the same conditions as in Example 1. After curing was completed, the glass plate was released from the mold to obtain a laminate with a thickness of about 11 mm in which polycarbonate resin and unsaturated polyester resin were firmly adhered.

Example 4 Two polycarbonate resin sheets having a partially cured primer layer on one side were manufactured in the same manner as in Example 1. On the other hand, both surfaces of a 5 mm thick FRP sheet manufactured by a conventional method were sanded in advance, and an unsaturated polyester resin having the same composition as in Example 1 was cast on one side. One of the polycarbonate resin sheets with a primer layer on top of it.
The sheets were squeezed so that the primer layer was in contact with the unsaturated polyester resin, and the sheets were degassed and pressure-bonded.
Immediately, this laminate was turned over, the unsaturated polyester resin was similarly cast on the other side of the FRP sheet, and another polycarbonate resin sheet having a primer layer was placed and degassed and pressed. Immediately after clamping the periphery, the laminate was placed in a heating furnace at 60 to 80°C, heated for 60 minutes, and then allowed to cool.

The thickness of the obtained laminate was about 10 mm, the adhesion between each layer was strong, and the weather resistance was not much different from that of Example 1.

Example 5 A polycarbonate resin sheet of the same size and type as in Example 1 was coated on one side with "Goserak CKS-UV" (trade name, Nippon Gosei Kagaku Kogyo Co., Ltd.), which does not contain solvents or low-boiling monomers, as an ultraviolet curable primer. Co., Ltd. sales) to the thickness using a wire coater.
It was applied to 50μ. Immediately turn on the high pressure mercury lamp HO2-L-
21 (sold by Aigra Graphics Co., Ltd.) for 4 seconds from a height of 50 mm to partially cure a part of the primer, and then cure the primer at about 25°C for about 15 minutes using the same ultraviolet irradiation device as in Example 1. The primer was partially cured to the extent that the primer surface was slightly tacky.

When a laminate was manufactured in the same manner as in Example 1 using two polycarbonate resin sheets having this partially cured primer layer, a good laminate having the same physical properties as in Example 1 was obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a polycarbonate resin sheet coated with a primer according to the present invention, FIG. 2 is a sectional view showing the primer being irradiated with ultraviolet rays, and FIG. 3 is a sectional view of a casting mold. Fourth
5 and 6 are cross-sectional views showing three examples of laminates obtained by the present invention. 1, 11, 12...UV curable primer,
2, 9, 10, 14, 15... Polycarbonate resin sheet, 3... Ultraviolet lamp, 5... Gasket, 8, 13... Cured synthetic resin.

Claims (1)

[Claims] 1. In a method for manufacturing a synthetic resin laminate having a polycarbonate resin surface layer on at least one side, an ultraviolet curable primer is applied to one side of a polycarbonate resin sheet or film, and ultraviolet rays are irradiated to form the synthetic resin laminate. The primer is partially cured without being completely cured, and then a sheet or film forming another surface layer is placed at a distance so as to face the partially cured primer layer, and the two sheets or A method for producing a synthetic resin laminate, comprising filling a liquid curable synthetic resin raw material between films and curing the material. 2. Two polycarbonate resin sheets or films having a partially cured primer layer on one side are arranged with a gap between them so that the partially cured primer layers face each other, and a liquid curable resin is placed between the two sheets or films. The method according to claim 1, characterized in that the synthetic resin raw material is filled and cured. 3. The method according to claim 1, wherein the ultraviolet curable primer does not substantially contain a solvent that easily dissolves the polycarbonate resin. 4. The method according to claim 3, wherein the ultraviolet curable primer is substantially free of low-boiling monomers that are easily soluble in polycarbonate resins.