JP3534514B2 - Coated surface protection sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated surface protective sheet which is used for the purpose of protecting and training a coated surface when a three-dimensional pattern is cured and formed using a resin or the like.

[0002]

2. Description of the Related Art Conventionally, as a method for imparting a three-dimensional pattern, a curl fit printing method for imparting a three-dimensional pattern on a curved surface using a predetermined machine, a method for using an ink containing a UV crosslinking agent, etc. are generally known. There is.

[0003]

However, in the above-mentioned curl-fit printing, there is a problem that it takes a long time to cure because the sheet overlaid on the surface for the purpose of protecting the coated surface delays the drying of the coating film. Further, when heat drying is performed to shorten the curing time, heat is trapped between the coated surface and the sheet, and the printed three-dimensional shape is deformed. Moreover, if the three-dimensional shape is large,
There is a problem in that it takes too much time because a larger heat capacity is required for heat drying.

Further, even in the method of curing using an ink containing a UV cross-linking agent, the conventional protective sheet used for protecting the coated surface has poor air permeability, so after natural drying,
There is a problem that it takes time to cure naturally. In addition, most of the above UV-crosslinking agent-containing inks are of a type that generates gas during curing, but this gas cannot escape from the protective sheet and accumulates between the inside of the sheet and the surface of the coating film, resulting in a large number of minute particles. A convex part (bubbling shape) is generated. For this reason, when the protective sheet is peeled off, the surface of the formed three-dimensional pattern tends to be rough like a chaff. further,
When a colored paint is used, there is a problem that the resin that can be used for printing is limited to a special resin because it reacts with ink or the like to change color or generate odor.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a coated surface protection sheet which can smoothly be naturally dried and naturally cured when a three-dimensional pattern is formed.

[0006]

In order to achieve the above object, the coated surface protection sheet of the present invention has an average surface roughness of the surface to be closely adhered to the object to be protected set to 1 to 10 μm, and at least A polymer porous sheet having a light transmittance of 50 to 100%, which has a plurality of continuous pores communicating with each other in the sheet thickness direction and has air permeability such that the Gurley value X falls within the range of the following formula (1). It is configured to be.

[Equation 2] (0 ≦ X ≦ 5) seconds / 100 cm ³ (1)

Next, an embodiment of the present invention will be described.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the material of the polymer porous sheet used in the present invention include plastics such as polyethylene, polypropylene, polystyrene and polyamide. Among them, it is preferable to use ultra-high molecular weight plastics. . These plastics are usually in powder form and may be used alone or in combination of two or more kinds.

Examples of the ultra high molecular weight plastics include ultra high molecular weight polyethylene (hereinafter referred to as "UHMWPE"), ultra high molecular weight polypropylene, and ultra high molecular weight polyamide.

The molecular weight (measured by the viscosity method) of the above ultra-high molecular weight plastic is peculiar in that it is much larger than usual ones. For example, the molecular weight of ordinary polyethylene or polypropylene is about 100,000 or less, while that of UHMWPE or ultra high molecular weight polypropylene is about 500,000 or more. Further, the molecular weight of ordinary polyamide is 5,000 or less, whereas that of ultra high molecular weight polyamide is about 40,000 or more.

As a commercially available product of the above ultra-high molecular weight plastic, for example, UHMWPE is "Hi-Zex million".
(Mitsui Petrochemical Industry Co., Ltd.), “Hostalen GUR” (Hoechst Co.) and the like are known. Ultra high molecular weight polypropylene is "HIPOL" (Mitsui Petrochemical Co., Ltd.)
Etc. are known. Furthermore, "Daiamide" (manufactured by Daicel Industries Ltd.) is known as an ultrahigh molecular weight polyamide.

In order to obtain a polymer porous sheet used in the present invention using the above plastic material, a method of sintering the material powder by sandwiching it with a hot press, or a method of filling the material powder in a mold and sintering the same. After that, a porous body is obtained, and then a sheet-like method is formed by cutting or the like.

As a specific example of the sintering method using the above-mentioned mold, for example, the above-mentioned material powder is filled in a mold, the powder is pressurized at a predetermined pressure, and then the temperature is maintained above the melting point of the polymer material. A method is known in which a block-shaped porous body having continuous pores is obtained by sintering in a heating furnace, cooling, and releasing from the mold.

However, in the above method, the degree of porosity is low in the vicinity of the outer peripheral portion of the block-shaped porous body and the degree of porosity is high in the central portion, so that the porous structure of the obtained sheet becomes uneven. Cheap. Therefore, it is preferable to use the method previously proposed by the present inventors (Japanese Patent Publication No. 5-66855) as an improvement plan of the above method. That is, in this method, a polymer material is first filled in a mold, heated at a temperature lower than the melting point of the polymer material, and then pressurized at a predetermined pressure to obtain a preform. Next, this preform is placed in a reduced pressure atmosphere to remove air from the preform, and then sintered in a steam atmosphere heated above the melting point of the polymer material, and after cooling, the gold This is a method of removing the mold from the mold to obtain a block-shaped porous body in which continuous pores are formed. By cutting the porous body obtained by this method to a predetermined thickness, a uniform sheet-shaped porous body can be easily obtained with an arbitrary thickness.

The thus obtained polymer porous sheet used in the present invention is required to have an average surface roughness of at least one surface of 1 to 10 μm, and particularly 2 to 5 μm. Is preferred. That is, when the average surface roughness is less than 1 μm, the coating film adheres to the sheet and peels off when the sheet is peeled off after the sheet is adhered to the coated surface. This is because when it is peeled off after being brought into close contact with the work surface, the unevenness of the sheet is transferred to the coated surface, the surface is roughened, and the coating film peels off. In addition, even if both surfaces of the polymer porous sheet are set to have an average surface roughness within the above range, there is no problem with the role of the coated surface protection sheet. In this way, there is no problem even if any surface is brought into close contact with the coated surface, and thus handling is convenient.

The air permeability of the polymeric porous sheet used in the present invention has a Gurley value X (0≤
It is necessary to set X ≦ 5) seconds / 100 cm ³ . Above all, (0 ≦ X ≦ 1) seconds / 100 cm ³
It is preferable to set to. That is, the Gurley value is 5
This is because if it exceeds sec / 100 cm ³ , the drying at the time of forming the initial coating film is hindered and the sheet and the coated surface are completely adhered. The porosity of the polymer porous sheet is preferably 10 to 70%, and more preferably 20 to 45%. That is, by setting the porosity within this range, preferable air permeability can be ensured. The plurality of continuous pores that communicate with each other may communicate not only with the thickness direction but also with the surface direction of the polymer porous sheet.

The coated surface protection sheet made of the polymer porous sheet thus obtained protects the coated surface forming the three-dimensional pattern when the three-dimensional pattern is formed.
It is used by covering the coated surface. Since the average surface roughness of the surface of the coated surface protective sheet that is brought into close contact with the object to be protected is limited as described above, the irregularity of the coated surface when peeled off can be suppressed as much as possible. Moreover, since the coated surface protection sheet has a certain level of air permeability due to the voids formed by a plurality of continuous pores communicating at least in the sheet thickness direction, natural drying of the coated surface covered with this sheet is prevented. Never. Therefore, it is possible to significantly reduce the time required for natural drying and natural curing, which conventionally took a long time, and it is not necessary to perform heat drying. Even if it is heat-dried, since it has the above-mentioned air permeability, heat is accumulated inside the sheet and the shape of the three-dimensional pattern is deformed, or the generated gas is accumulated and many minute convex parts (brushed shape) are formed. It never happens.

The polymeric porous sheet used as the coated surface protection sheet is not only used as a sheet, but also formed as a bag and used as a bag for containing and protecting the entire printed matter.

Further, among the above polymer porous sheets,
It is necessary to use the one whose light transmittance is set to 50 to 100%
There are are suitable for use in the protection of printed coated surface with UV crosslinker containing ink. That is, the light transmittance is 50
% Less natural curing rate by light becomes slower delay coating formed in, or scratches due to external factors, that rubbing Oko
However , those having a light transmittance in the above range can be smoothly cured by natural light.

Next, examples will be described together with comparative examples.

[0021]

Example 1 A polymer porous sheet made of ultra-high molecular weight polyethylene having a molecular weight of 6 million (measured by a viscosity method), having a thickness of 100 μm, a porosity of 25% and a micropore diameter of 30 μm was prepared. This polymer porous sheet has an average surface roughness of 2.5 μm, a light transmittance of 86%, and a Gurley value of 0.5 seconds /
It was 100 cm ³ . The average surface roughness is measured with a contact needle type surface roughness meter, and the light transmittance is measured according to JIS K710.
5, and the Gurley value was measured according to JIS P 8117. Then, this polymer porous sheet was cut into a length of 12 cm and a width of 25 cm.

[0022]

Examples 2 to 7 As shown in Table 1 below, the conditions of the polymeric porous sheet made of ultra-high molecular weight polyethylene were changed. Six types of sheets were obtained in the same manner as in Example 1 except above.

On the other hand, curl fit printing was carried out on a Pioneer car stereo operation panel, and after 3 minutes, the sheet obtained in each of the above examples was mounted on the printing coated surface for protection. After passing through the assembly line, about 10 minutes later, the product was packaged as it was. Then, 50 pieces were sampled and the state of transfer of the coating film to the polymer porous sheet and the surface state of the coated surface were observed. As an accelerated test, 3 minutes after curl-fit printing was performed on a flat surface, the polymer porous sheet was covered, a weight of 500 g was placed on a diameter of 2 cm, and the state of transfer and surface roughness of the coating film was maintained at 80 ° -96 hours for 20 minutes. I observed them individually. The results are shown in Tables 2 and 3 below.

[0024]

[Table 1] (Note 1) Gurley value is measured on the 0.1 sec / 100 cm ³ units, the measurement not less than 0.1 sec / 100 cm ^3, considered similarly to the Gurley value of 0.0 sec / 100 cm ³ To be

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

Comparative Examples 1 to 7 As shown in Table 4 below, the sheet conditions were changed. However, each sheet was cut into a length of 12 cm and a width of 25 cm as in Example 1. Then, these comparative products were evaluated in the same manner as in Examples 1 to 7 above. The results are shown in Tables 5 and 6 below.

[0028]

[Table 4] (Note 2) The same as Note 1 in Table 1 above. (Note 3) SPV 364 series (manufactured by Nitto Denko Corporation) was used.

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

Examples 8 and 9 and Comparative Examples 8 and 9 Carl fit printing was performed on a car stereo operating panel made of sheet-like ABS resin, and a clear coat agent (a prepolymer of polyester acrylate and an acrylic monomer) was used as a photopolymerization initiator on it. (Benzoin alkyl ethers) were added and applied. This was placed under an indoor fluorescent lamp and kept for 3 minutes, and then covered with a polymer porous sheet similar to Example 1 except that the light transmittances were 86%, 55%, 45% and 20%, respectively. Hold for another 7 minutes. Then, the porous sheet was peeled off, and the pencil hardness (JIS K 5401) of the coating film surface was measured. Therefore, 3H or more was judged as a pass. The results are shown in Table 7 below.

[0032]

[Table 7]

[0033]

INDUSTRIAL APPLICABILITY As described above, the coated surface protection sheet of the present invention is used by covering the surface of the coated surface in order to protect the coated surface forming the three-dimensional pattern when forming the three-dimensional pattern. To be Then, the coated surface protection sheet, because the average surface roughness of the surface to be adhered to the protected object is limited within the above range, the disturbance of the coated surface when the coated surface protection sheet is peeled off is unlimited. Can be suppressed. Furthermore, since this coating surface protection sheet has a certain level of air permeability ensured by the voids consisting of a plurality of continuous pores communicating at least in the sheet thickness direction, natural drying of the coating surface covered with this sheet is hindered. Never. Therefore, it is possible to significantly reduce the time required for natural drying and natural curing, which conventionally took a long time, and it is not necessary to perform heat drying. Even if it is heat-dried, since it has the above-mentioned breathability, heat is accumulated inside the sheet and the shape of the three-dimensional pattern is deformed, or the generated gas accumulates to form minute protrusions (bubbling shape). There is nothing to do.

Continuation of front page (56) References JP-A 1-210376 (JP, A) JP-B 5-66855 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 9 / 24 B41M 3/06

Claims (2)

(57) [Claims] 1. An average surface roughness of a surface to be brought into close contact with an object to be protected is set to 1 to 10 μm, and a plurality of continuous pores communicating at least in a sheet thickness direction are provided, and a Gurley value X is represented by the following formula. A coated surface protection sheet comprising a polymeric porous sheet having air permeability within the range of (1) and having a light transmittance of 50 to 100% . [Equation 1] (0 ≦ X ≦ 5) seconds / 100 cm ³ (1) 2. The polymer porous sheet is an ultra high molecular weight material.
Coated surface protection sheet of claim 1, wherein ing polyethylene sintered porous sheet.