JP4671942B2 - Laminate for laser printing - Google Patents

Description

The present invention relates to a laminate for laser printing that performs printing with a laser beam, and more specifically, after being applied to a substrate, it can withstand long-time use under high temperature conditions, has good workability, and does not require re-use of peeling. The present invention relates to a laminate for laser printing used for possible labels.

For the purpose of product management and quality assurance, it is widely practiced to attach labels, sheets or the like on which individual information such as production numbers and expiration dates are printed to individual products.

As a method for printing on the label sheet, for example, a method of printing liquid ink with a plate, a method of printing ink by thermal transfer using an ink ribbon, a method of printing ink using an ink jet printer, etc. are used. However, it is complicated and difficult to print different pieces of information individually on a large number of products by the above-described method.

Therefore, the surface layer and the base layer of the base material are provided as a combination of different colors having a brightness difference that can easily recognize the concealment layer that absorbs laser light and can be removed by heat generation and destruction. A laminated body for laser printing has been proposed that can perform desired printing of the color of the underlayer by irradiating with the output adjusted and irradiating the pattern such as characters so as to remove the concealing layer (Patent Document 1,). Patent Document 2).

On the other hand, a laser-printed label with a serial number or the like is also used for authentication labels, approval labels, etc. for machines, automobile parts, etc., but if the place where the label is used is in an engine room, the operating temperature is 50 It may also rise above ℃.
In addition, even in automobiles that are used in the tropics and deserts, etc., authentication labels that are affixed to various places inside and outside the vehicle are exposed to intense direct sunlight or are exposed to harsh temperature environments. There are many.

When a normal laser-printed label is used under such severe temperature conditions, cracks or curls occur, causing troubles such as destruction of automobiles without waiting for their useful life.

Although an attempt was made to use a general label as a laminate as a laser-printed laminate, the printability and handling properties were insufficient and could not be put to practical use.

In addition, a method of providing a heat-resistant resin such as a polyimide resin and a polyamide resin, which are generally used, as a colored resin layer as one layer constituting a laminated label for laser printing is also conceivable. Many of them are hard and brittle resin layers. For example, when used as labels to be attached to uneven curved surfaces on the surface of automobiles and motorcycles and machine parts, there is a problem that the end part is raised due to lack of flexibility. Occurred.

In the Japanese Patent Application No. 2005-204989 (Patent Document 3: unpublished), the present inventors have disclosed a laser-printable laminate comprising a colored resin layer, a colored breaking layer comprising a crosslinked acrylic resin containing a glycol compound, and an adhesive layer. Therefore, a laminate that can be attached to a curved surface and has brittleness has been proposed. However, since the laminate is soft and does not have an appropriate stiffness, there is a problem in that workability is poor when labeling and attaching to a substrate.
JP 09-123606 A JP 09-123607 A Japanese Patent Application No. 2005-204989

The problem to be solved by the present invention is a laminate for laser printing capable of clear printing, and appearance defects such as cracks do not occur even when exposed to harsh temperature conditions such as deserts and tropics for a long time. It is providing the laminated body for laser printing which is good also in pasting workability.

The inventors have
(A) A colored layer having a thickness of 10-30 μm, made of an acrylic resin, having a tensile elongation at break of less than 5%, and being the outermost layer when the laminate is bonded to a substrate;
(B) a fracture layer having a thickness of 30 to 150 μm, laminated on the colored layer, having a visible color difference from the colored layer, made of an acrylic resin, and having a tensile elongation at break of less than 8%;
(C) a support layer having a thickness of 40-80 μm, laminated on the fracture layer, made of an acrylic resin and having a tensile elongation at break of 12% or more,
The above problem was solved by an acrylic laminate having a thickness of 100 μm to 200 μm.

In the laminate of the present invention, by removing the colored layer by breaking it into a desired shape by laser light irradiation, the color of the support layer is visually recognized at the removed portion, and desired printing and images can be expressed.

The laminate of the present invention does not cause appearance defects such as cracks even when exposed to harsh temperature conditions for a long time, does not peel off, and can be applied following a curved surface, especially when labeled. It is a laminate for laser printing that has good workability and cannot be reused after peeling.

The laminated body of this invention is demonstrated in detail below.
The laminate of the present invention is a laser-absorbing colored layer that adjusts the output of the laser light, collects it, and irradiates it in a pattern such as letters. Or exothermic, decomposed, and ashed, removed in a pattern, and the removed portion exhibits the color of the destructive layer or support layer, and is a laminate having layers of different colors.

In the laminate of the present invention, a colored layer that can be removed by laser light irradiation exists on the surface of the laminate. The colored layer is formed by laminating or coating a colored resin obtained by adding a colorant to an acrylic resin with a predetermined thickness on the breaking layer.

The resin constituting the colored layer used in the present invention is preferably a crosslinked acrylic resin crosslinked with an amino resin-based crosslinking agent. The cross-linked acrylic resin referred to here is a resin obtained by cross-linking an acrylic resin having a functional group with a cross-linking agent or the like. An acrylic resin is a resin whose main component is a resin produced by polymerization of an acrylic monomer or a methacrylic monomer, and the main component means a resin containing 50% or more of an acrylic resin as a resin component.

Examples of the acrylic monomer include resins obtained by copolymerization using acrylic acid ester, methyl acrylate, propyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, and the like as monomers, Examples of the methacrylic acid monomer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, and the functional groups include a hydroxyl group, a mercapto group, an epoxy group, Examples include an amide group and a methylolated acrylamide group.

Among the resins, a resin obtained by copolymerizing a monomer having a hydroxyl group as a functional group is preferable from the viewpoint of control of pot life after mixing with a crosslinking agent and tensile breaking elongation after crosslinking. In view of this, a resin copolymerized with methyl methacrylate (MMA) as a monomer is also suitable.

An amino resin-based crosslinking agent is used as the crosslinking agent for the colored layer of the present invention. Amino resin-based crosslinking agents include melamine-based, guanamine-based, and urea-based crosslinking agents, but melamine-based crosslinking agents can be suitably used in consideration of physical properties such as heat resistance and control of tensile elongation at break after crosslinking. .
The crosslinking agent is used in an amount of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, based on the reactive functional group of the resin.

The thickness of the colored layer is 10 to 30 μm, preferably 10 to 20 μm. If the thickness is 10 μm or more, the concealability can be sufficiently secured, and if it is less than 30 μm, the irradiated part can be completely removed by laser light irradiation.

Further, the pigment content of the colored layer is preferably 1 to 300% by weight, preferably 5 to 250% by weight, more preferably 8 to 200% by weight, based on the acrylic resin. . If the pigment content is less than 1% by weight, the concealment property is generally low and it is difficult to provide contrast with the back surface. If the pigment content is 300% by weight or more, the colorant layer becomes too brittle, Cracks may occur in the colorant layer.

The colorant used in the colored layer of the present invention and the support layer and destruction layer described below is not particularly limited, but it is a weatherable and durable colorant that can be removed by laser light irradiation and can be used for a long period of time. Specifically, the Color Index 3rd published by The Society of Dyers and Colorists
You can choose from the colorants listed in Edition (1971) and Supplements (1975). The colorant names shown below are the Color Index defined in the same document.
According to Generic Name. For example, Bk-1 means CIPigment Black1, Bk represents black (Black), and W represents white.

As the color of the colorant, any color tone such as yellow, orange, red, purple, blue, green, brown, black and white can be used. Usually black or white is used. Specific examples of preferred colorants are given below.

Examples of preferable black pigments include organic pigments and inorganic pigments.Examples of preferable organic pigments include aniline black (Bk-1) and perylene black (Bk-31). ,

Examples of inorganic pigments include carbon black (Bk-31), carbon black (Bk-7), carbon black (Bk-9), iron black (Bk-11), Examples thereof include cobalt oxide pigments (Bk-13).
Among them, a preferable pigment is carbon black (black) in the form of amorphous or graphite. The preferred average particle size of carbon black is in the range of 10 to 500 nm, particularly preferably in the range of 15 to 120 nm, and various commercially available carbon blacks having a fine average particle size can be used.

Further, as the preferred white pigment, inorganic pigments are preferable, for example, zinc white (W-4), zinc sulfide (W-7), titanium dioxide (W-6), calcium carbonate (W-18). , Clay (W-19), barium sulfate (W-21), alumina white (W-24), silica (W-27), muscovite (W-20), tank (W-26), etc. Can do.

Among them, a preferable pigment is rutile type titanium oxide (white). The preferable average particle diameter of titanium oxide is in the range of 10 to 500 nm, particularly preferably in the range of 20 to 100 nm, and various commercially available types of titanium oxide having a fine average particle diameter can be used.

In addition to the pigment, the colored layer can contain mica and aluminum powder as long as the colorability and weather resistance are not affected.

When carbon black or titanium oxide is used, the colorant can itself be a compound that converts laser light into heat. However, if the colorant is not absorptive with respect to the laser light, a compound may be required to convert the laser light into heat, in which case a mixture of pigments, or one or more pigments and a laser Mixtures with one or more compounds that can convert light into heat can also be used.

Examples of the compound for converting laser light into heat include carbon black, cyanine-based, phthalocyanine-based, inorganic-based infrared absorbers, and the like.

The laminated body of this invention is laminated | stacked on the said colored layer, and has a destruction layer which consists of acrylic resin. The breaking layer is preferably made of a cross-linked acrylic resin. As the acrylic resin, a resin similar to the resin used for the colored layer described above is used.
The fracture layer is formed of a resin imparted with brittleness by cross-linking or addition of a brittleness imparting component described later, and the tensile fracture elongation thereof needs to be less than 8%.

Examples of the crosslinking agent used for crosslinking the acrylic resin of the destructive layer include melamine crosslinking agent, isocyanate crosslinking agent, epoxy crosslinking agent, polyamine crosslinking agent, aldehyde crosslinking agent, etc., heat resistance, crosslinking Considering physical properties such as control of the hardness afterwards, a melamine-based cross-linking agent and an isocyanate-based cross-linking agent can be preferably used as long as the tensile elongation at break is satisfied.

The said melamine type crosslinking agent used for a colored layer and the said isocyanate type crosslinking agent used for a support layer can be suitably used in the range which satisfies the said tensile breaking elongation.

The crosslinking agent is used in an amount of 0.1 to 1.5 equivalents, preferably 0.2 to 1.3 equivalents, particularly preferably 0.3 to 1.2 equivalents, relative to the functional group equivalent of the fracture layer resin. If the amount of the crosslinking agent is too large, it becomes too brittle and the workability is impaired, and if it is too small, it becomes difficult to break.

A component imparting brittleness may be added to the fracture layer.
As the component imparting brittleness, inorganic particles such as glass beads, silica and calcium carbonate; organic particles such as acrylic beads, styrene beads and silicone beads; and the like can be used, but the particle size distribution is narrow. Glass beads, acrylic beads, styrene beads, and silicone beads are preferable, and glass beads and acrylic beads are most preferable in consideration of heat resistance.

When inorganic particles or organic particles are used as the brittleness imparting component, the average particle size needs to be equal to or less than the thickness of the brittle layer, and is 1 to 150 μm, preferably 5 to 100 μm, particularly preferably 10 to 80 μm.
If the particle diameter is 1 μm or less, it is impossible to impart brittleness, and if it is 150 μm or more, cracks are likely to occur during the pasting operation.

The content of the brittleness-imparting component is 10 to 280% by volume, preferably 10 to 200% by volume, particularly preferably 30 to 100% by volume, based on the resin.
If the brittleness-imparting component is 10% by volume or less, the brittleness-imparting effect is not observed, and if it is 280% by volume or more, voids are generated between the particles, and cracks may occur during the pasting operation.

In addition, the destructive layer needs to be colored in a color having a color difference visible to the colored layer, and the pigments that can be used for the colored layer can be used for coloring. The pigment content of the destructive layer may contain 10 to 500% by weight, preferably 30 to 300% by weight, more preferably 50 to 250% by weight of the colorant with respect to the acrylic resin. If the pigment content is less than 10% by weight, it is impossible to ensure concealment, and if it is 500% by weight or more, it cannot be held as a film.

The laminated body of this invention is laminated | stacked on the said destruction layer, and has a support layer which consists of acrylic resin. The support layer may be colored or transparent, but when colored, the support layer is preferably colored in the same hue as the destructive layer, and the pigments that can be used in the above-described colored layer can be used as well. As the acrylic resin, a resin similar to the resin used for the colored layer described above is used, but flexibility with a tensile elongation at break of 12% or more is required, and the crosslinking agent and additive are different from the colored layer.

As the crosslinking agent used for crosslinking of the acrylic resin of the support layer, an isocyanate crosslinking agent is particularly preferable, and an aliphatic isocyanate or an alicyclic isocyanate is particularly preferable in consideration of flexibility after crosslinking.
Specifically, for example, transcyclohexane 1,4-diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, 4,4′-dicyclohexylbutane diisocyanate, lysine diisocyanate, isophorone diisocyanate, lysine ester triisocyanate, 1,6 , 11-undecatriisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, and the like.

The crosslinking agent is used in an amount of 0.1 to 1.3 equivalents, preferably 0.2 to 1.0 equivalents, relative to the functional group equivalent of the support layer resin. When the amount of the crosslinking agent is too large, flexibility is impaired, and when it is too small, heat resistance and durability are impaired.

The support layer may be colored or transparent, but when colored, the support layer is preferably colored in the same hue as the destructive layer, and the pigments that can be used in the colored layer described above can be used as well. The pigment content of the support layer is preferably 10 to 500% by weight, preferably 30 to 300% by weight, more preferably 50 to 250% by weight, based on the acrylic resin. If the pigment content is less than 10% by weight, it is impossible to ensure concealment, and if it is 500% by weight or more, it cannot be held as a film.

In order to maintain the flexibility of the support layer, a glycol compound can be used as a flexible agent. The glycol compound is a condensed compound of diol, such as ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, etc., and polymers include polyethylene glycol, polytetramethyl glycol (PTMG), THF-neopentyl glycol Copolymer (Asahi Kasei Co., Ltd., PTXG), etc., and polymer-type glycol compounds are easily available and priced from the viewpoint of the volatility of glycol itself, the degree of flexibility given per added amount, and water resistance. In view of the above, polytetramethyl glycol is particularly preferable.

The glycol compound may be contained in an amount of 1 to 10% by weight, preferably 2 to 8% by weight, particularly preferably 3 to 6% by weight, based on the resin composition.
If the glycol compound is 1% by weight or less, the film may be cracked only by bending at the time of sticking, and if it is 10% by weight or more, the film is not broken and can be peeled off.

The thickness of the support layer is 40 to 80 μm, preferably 50 to 60 μm. If the thickness is 40 μm or more, sufficient flexibility can be imparted to the laminate, and if it is less than 80 μm, destructiveness can be maintained.

The laminate of the present invention needs to have a tensile elongation at break of 5% to 30% as a laminate, preferably 10% to 25%.
If the tensile elongation at break is 5% or more, the work can be secured, and if it is less than 30%, it cannot be reused.

The tensile strength measured based on JIS K 7172 of the laminate of the present invention is 25 N / 10 mm or more, preferably 30 N / 10 mm or more. When the tensile strength is less than 25 N / 10 mm, the label is not stiff when the label is pasted and the pasting workability is deteriorated.

When the label comprising the laminate of the present invention is applied to a substrate and then peeled off by hand or instrument, the film breaks. Although the mechanism of fracture is various, a colored layer having a low tensile fracture strength is often cracked by peeling and cannot be restored. Known brittle laminates are hard and brittle with compositions that break at the time of peeling, so there are problems in workability and followability to the substrate when labeling and pasting, but the laminate of the present application is used as a support layer. By arranging a resin layer having a high tensile breaking strength and selecting the thickness of the three layers, it has both workability and destructibility.

The laminate of the present patent invention is further laminated with an adhesive layer that adheres the laminate to the substrate.
The adhesive layer has a thickness of 15 to 100 μm, preferably 20 to 70 μm, more preferably 25 to 45 μm. If the film thickness is 15 μm or more, the sheet is peeled off from the adherend and the workability such as bending of the adherend is good, and if the film thickness is less than 100 μm, the sticking suitability is good. This is advantageous in terms of cost.

Further, the adhesive strength of the adhesive layer was measured to be 5 N / 25.4 mm or more when the 180 ° folded peel test with a tensile tester was performed after being bonded to an adherend as a tape having a width of 25.4 mm and left for 24 hours. Are preferred. When the adhesive strength is less than 5N / 25.4 mm, the sheet may be peeled off from the adherend when the adherend to which the laminate is attached is bent.

The resin constituting the adhesive layer is not particularly limited, but an acrylic adhesive is preferable from the viewpoints of weather resistance, transparency, yellowing resistance, and the like, and the acrylic adhesive includes a tackifier as necessary. Additives such as ultraviolet absorbers, light stabilizers and antioxidants can be added.

The laminate of the present invention is a support layer forming resin in which a colored layer resin is printed on a process film or printed with a gravure and dried to form a colored layer, and a colorant is similarly dispersed on the colored layer. It is manufactured by coating or printing with gravure and drying, and then coating the support layer with a fracture layer forming resin or printing with gravure and drying in the same way. It can also be produced by a known lamination film production method such as a method of lamination by thermocompression bonding or adhesion by an adhesive, or a combination of these methods.

As shown in FIG. 1, the laminate 1 of the present invention includes, on the adhesive layer 4, a destructive layer 3 that breaks by peeling, a support layer 2, and a colored layer 1 that can be removed by laser light irradiation in this order. Are stacked. When the laminate is irradiated with laser light, the colored layer 1 is removed in the shape of laser irradiation, the support layer 2 is exposed, and a desired printed image or the like is formed by comparing the colors of the colored layer 3 and the support layer 2 It is.

Examples of lasers that can be irradiated include CO2 lasers, Nd: YAG lasers, excimer lasers, semiconductor lasers, semiconductor-excited solid state lasers, Ar lasers, N2 / Dye lasers, and HeCd lasers. However, a relatively easy CO2 laser, Nd: YAG laser, or the like is used.

The laminate of the present invention can be individually printed according to the purpose by the laser printing device, and the serial number and date are printed for the purpose of product management and quality assurance. Effectively used in environments exposed to high temperatures for a long time as printed labels or sheets for displaying individual information such as deadlines, etc. Once affixed labels etc. are destroyed, they will be destroyed. Fraud can be prevented.

Reference example 1
50 parts by weight of acrylic resin KP-1876 (made by Nikka Polymer Co., Ltd.), 50 parts by weight of acrylic resin 2100U5 (made by Nippon Carbide Industry Co., Ltd.), 5 parts by weight of CAB (MIBK 20% solution), melamine-based crosslinking agent MS-11 18 parts by weight (manufactured by Sanwa Chemical Co., Ltd.), 4.5 parts by weight of curing catalyst CT-5 (manufactured by Sanwa Chemical Co., Ltd.), 15 weight by colorant UTCO-591B (manufactured by Dainichi Seika Kogyo Co., Ltd.) Part, MIBK 15 parts by weight, and toluene 30 parts by weight were mixed to prepare a black resin solution for the colored layer.

Reference example 2
50 parts by weight of acrylic resin KP-1876 (manufactured by Nippon Carbide Industries Co., Ltd.), 20 parts by weight of CAB (MIBK 20% solution), 100 parts by weight of colorant UTCO-501 white (manufactured by Dainichi Seika Kogyo Co., Ltd.), melamine -Based crosslinking agent MS-11 (manufactured by Sanwa Chemical Co., Ltd.) 9 parts by weight (1.0 equivalent to the reactive functional group of the resin), curing catalyst CT-5 (manufactured by Sanwa Chemical Co., Ltd.) 3 weights Part, 2 parts by weight of a glycol compound PTMG-1000M (manufactured by Sanyo Chemical Industries, Ltd.) and 5 parts by weight of Solvesso 100 (manufactured by ExxonMobil) were mixed to prepare a white resin solution for a fracture layer.

Reference example 3
50 parts by weight of acrylic resin 2100U5 (manufactured by Nippon Carbide Industries Co., Ltd.), 100 parts by weight of colorant UTCO-501 white (manufactured by Dainichi Seika Kogyo Co., Ltd.), isocyanate-based crosslinking agent Sumijoule N75 (Sumitomo Chemical Co., Ltd.) )) 20 parts by weight (1.0 equivalent with respect to the reactive functional group of the resin), glycol compound PTMG-1000M (manufactured by Sanyo Chemical Industries, Ltd.) 6 parts by weight, Solvesso 100 (manufactured by ExxonMobil) 5 A white resin solution for a support layer was prepared by mixing parts by weight.

Reference example 4
100 parts by weight of acrylic pressure-sensitive adhesive PE-121 (manufactured by Nippon Carbide Industries Co., Ltd.) and 1.8 parts by weight of crosslinking agent CK-401 (manufactured by Nippon Carbide Industries Co., Ltd.) are mixed to form a pressure-sensitive adhesive solution. A was prepared.

Example 1
The black resin solution for colored layer obtained in Reference Example 1 was applied to a PET film (S75 manufactured by Teijin DuPont Films Ltd.), dried at 90 ° C. for 2 minutes, then at 140 ° C. for 3 minutes, and colored with a thickness of 15 μm. A layer was formed.
On this colored layer, the white resin solution for the support layer obtained in Reference Example 2 is applied so that the thickness after drying is 30 μm, dried under the same conditions as the colored layer, and the colored layer and the destruction layer are laminated. A film was prepared.
Next, the white resin solution for the support layer obtained in Reference Example 3 was applied to the destruction layer side of the film in which the colored layer and the destruction layer were laminated so that the thickness after drying was 70 μm, and the colored layer and the support A layered product of layers and destructive layers was obtained.
Furthermore, the adhesive solution A obtained in Reference Example 4 was applied to a PET film (trade name MRG50, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) and dried at 100 ° C. for 2 minutes to form an adhesive layer having a thickness of 30 μm. did. The laminated body was bonded to this so that the surface of the support layer was in contact with the adhesive layer, and peeled from both PET films, thereby producing a laminated body for laser printing.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Example 2
A laminate for brittle laser printing was formed in the same manner as in Example 1 except that the thickness after drying of the destructive layer was 60 μm and the thickness after drying of the support layer was 40 μm.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Example 3 and Example 4
Example 1 except that the resin of the support layer was changed to 50 parts by weight of an acrylic resin SZ6226 (manufactured by Nippon Carbide Industries Co., Ltd.) (Sumijoule corresponds to 0.9 equivalent to the reactive functional group of the resin). In the same manner as in Example 2, a laminate of a colored layer, a fracture layer, and a support layer was obtained. Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Example 5
The resin of the fracture layer was changed to 50 parts by weight of acrylic resin 2100U5 (manufactured by Nippon Carbide Industries Co., Ltd.), and isocyanate crosslinking agent Coronate HK (Nippon Polyurethane Industry Co., Ltd.) instead of MS-11 and CT-5 as crosslinking agents )) 7 parts by weight (1.1 equivalents with respect to the reactive functional group of the resin), and in the same manner as in Example 1, a film in which a colored layer and a destruction layer were laminated was produced. Next, the acrylic resin of the white resin solution for the support layer was changed to SZ6227 (manufactured by Nippon Carbide Industries Co., Ltd.) (Sumijoule corresponds to 0.9 equivalent to the reactive functional group of the resin), A support layer was formed using a blending solution containing 4 parts by weight of PTMG-1000M to obtain a laminate of a colored layer, a fracture layer, and a support layer. Further, in the same manner as in Example 1, an adhesive layer was formed to form a laminate for brittle laser printing.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Example 6
A laminate was formed in the same manner as Example 5 except that the thickness after drying of the destructive layer was 60 μm and the thickness after drying of the support layer was 40 μm.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Comparative Example 1
A brittle laser-printed laminate was formed in the same manner as in Example 1 except that only the destructive layer was used, the thickness of the colored layer was 20 μm, and the thickness of the destructive layer after drying was 80 μm.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Comparative Example 2
A laminate for brittle laser printing was formed in the same manner as in Example 1 except that only the support layer was used, the thickness of the colored layer was 20 μm, and the thickness of the support layer after drying was 80 μm.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Comparative Example 3 to Comparative Example 5
The composition and thickness of the colored layer, the fracture layer, and the support layer were changed as shown in Table 1 to obtain a laminate.
Further, in the same manner as in Example 1, an adhesive layer was formed to form a laminate for brittle laser printing.
Tables 1 and 2 show the composition of the obtained laminate, tensile measurement results, and test results.

Each physical property was measured by the following evaluation methods.
(1) Tensile elongation at break (JIS K 7172)
Tensile tester = Tensilon TM-100 (Toyo Baldwin)
Specimen width = 10 mm Grasp interval = 100 mm Tensile speed = 200 mm / min Measured 5 times, and the average value was obtained.
(2) Tensile strength at break (JIS K 7172)
Same as tensile elongation at break

(3) Reusability A 1.5 cm × 5 cm laminate was affixed to a white painted plate and left in an atmosphere at 23 ° C. for 72 hours.
Thereafter, the laminate was peeled off from the painted plate using a cutter knife. At that time, it was evaluated as “not reusable” when it could not be re-applied due to destruction of the laminated product, etc., and “reusable as possible” when it could be reused.
The above test was performed 10 times for each material and evaluated according to the following criteria. ○: Not possible 9
More than
△: Impossible 7-8 times ×: Impossible 6 times or less

(4) Affixing workability A 1.5 cm × 5 cm laminate label with an adhesive layer and release paper is prepared, peeled off from the release paper, and attached to a white coated plate. It was confirmed whether the colored layer was broken (cracked) during the pasting operation.
Fifty labels were pasted and evaluated according to the following criteria based on the number of labels destroyed during the pasting operation.
○
:
Destruction in 50 sheets is 1 or less △: Destruction in 50 sheets is 2 to 5 sheets ×: Destruction in 50 sheets is 6 sheets or more

(4) Character omission Using the LP-430 manufactured by SUN Corporation, the letter “A” was printed at a thickness of 130 μm, 250 μm, and 400 μm at an output of 10 W and a scan speed of 500 mm / s. The release paper was peeled off, and each character was observed with transmitted light from the pressure-sensitive adhesive layer side. The case where the laminate was not burned out by the laser was marked with ◯, and the case where the pressure-sensitive adhesive layer was burned out was marked with x.

(5) Character sharpness From the surface of the sample evaluated for character omission, the end of the printed character was observed using an optical microscope (OLYMPUS BX51) and judged according to the following criteria.
The character end is sharp and clean: ○
Burr is seen at part of the character end: △
Burr is generated at the entire character end: ×

(6) Barcode readability EAN128 pattern barcodes were printed under the same conditions as for character omission. This bar code was read 10 times with a bar code reader, and the case where it could be read 10 times was marked with ◯, and the case where it could not be read once was marked with x.

(7) A sample printed with the EAN128 pattern barcode in the same manner as in the heat resistance barcode reading test was left for 1000 hours in an environment of 150 ° C., and then read 10 times with a barcode reader. The case where it was possible was marked with ○, and the case where it could not be read even once was marked with ×.

FIG. 1 is a sectional view of a typical laminate for brittle laser printing according to the present invention. FIG. 2 is a cross-sectional view of a laminate for brittle laser printing according to the present invention in which beads are included in the fracture layer.

Explanation of symbols

1. 1. Colored layer 2. Destructive layer 3. Support layer 4. Adhesive layer beads

Claims (7)

A laminate for acrylic laser printing having the following resin layers (A) to (C) and a thickness of 100 μm to 200 μm.
(A) A colored layer having a thickness of 10-30 μm, made of an acrylic resin, having a tensile elongation at break of less than 5%, and being the outermost layer when the laminate is bonded to a substrate;
(B) a fracture layer having a thickness of 30 to 150 μm, laminated on the colored layer, having a visible color difference from the colored layer, made of an acrylic resin, and having a tensile elongation at break of less than 8%;
(C) a support layer having a thickness of 40-80 μm, laminated on the fracture layer, made of an acrylic resin and having a tensile elongation at break of 12% or more, A laminate for acrylic laser printing, wherein the laminate has a tensile elongation at break of 5% to 30%. The laminate for acrylic laser printing according to claim 1, wherein the tensile strength is 25 N / 10 mm or more. The laminate for acrylic laser printing according to any one of claims 1 to 3, wherein the acrylic resin is a crosslinked acrylic resin. The colored layer is white or black, The laminate for acrylic laser printing according to any one of claims 1 to 4. A laser printing label in which an adhesive layer is laminated on the side opposite to the colored layer of the laminate for laser printing according to claim 1. The laser according to any one of claims 1 to 6, wherein a laser print image is formed on the colored resin layer by irradiation with laser light, and is peeled off after being adhered to an adherend, whereby the colored layer is destroyed and cannot be reused. Print label.