KR20050074936A - The preparation method of adhesive attachment using photo-sensitive polyurethane resin and adhesive attachment made thereby - Google Patents

Abstract

   The present invention relates to a method for producing a pressure-sensitive adhesive by using a photopolymerizable polyurethane resin and to a pressure-sensitive adhesive obtained therefrom, wherein the manufacturing process includes: (1) polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), synthetic paper Surface-treating corona discharge on the front and rear surfaces of the non-hydrophilic adhesive substrate; (2) 34.2 to 40.5% by weight of vinyl monomer containing at least two or more double bonds, 5.2 to 9.0% by weight of a silicone composite having a double bond, 0.1 to 0.3% by weight of a photopolymerization initiator and a residual urethane-based oligomer having a double bond at the end; A pressure-sensitive adhesive layer coating step of mixing and applying to the rear surface of the attachment base material; (3) a pressing step of pressing the transparent release paper of the surface roughness 0.05-0.8s; And (4) irradiating UV-rays of 200-400 nm wavelength to a light amount of 500-5,000 mJ / cm 2 on the attached base material to which the transparent release paper is attached to photopolymerize.

Description

The preparation method of adhesive attachment using photo-sensitive polyurethane resin and adhesive attachment made by using a photopolymerizable polyurethane resin

The present invention relates to a method for producing a pressure sensitive adhesive using a photopolymerizable polyurethane resin and a pressure sensitive adhesive obtained therefrom. More specifically, the present invention relates to a method for producing a pressure-sensitive adhesive which can be repeatedly attached and detached without contaminating the surface to be adhered using the photopolymerizable polyurethane resin composition as a pressure-sensitive adhesive and a pressure-sensitive adhesive obtained therefrom.

Adhesives in the broad sense belong to the category of adhesives. However, the general adhesive is solidified by heating, humidification, photosensitization, volatilization, etc., but the adhesive maintains its fluidity for a long time. Existing pressure-sensitive adhesives collectively referred to as pressure sensitive adhesives (PSA) are classified into acrylic, hot melt, and natural rubbers, which are commonly used in industrial fields, in terms of raw materials used. It is classified into water-soluble emulsion type and functionally classified into permanent adhesive type, re-adhesive adhesive type, and special adhesive type.

In general, the acrylic pressure-sensitive adhesive is prepared in an emulsion form by dispersing an acrylic monomer having a reactive functional group in an acrylic resin, but may have a high adhesive strength, but it is difficult to effectively control the crosslinked structure exhibiting fluid cohesiveness, resulting in an adhesive. In addition, the operating temperature is narrow and flows down according to the temperature change, or after 10-15 hours after attachment, it is completely combined with the adherend by humidification, volatilization, etc., which damages the surface of the adherend or destroys the end face of the adherend. The use is limited to one.

Korean Patent No. 342101 and Utility Model No. 232152, etc., relate to recyclable packaging adhesive tapes, wherein the adhesive component is an acrylic polymer. It contains a special plasticizer of polypropylene glycol alkylphenyl ether type, which is easy to dissociate in weak alkali, so that it is easily dissolved in weak alkaline solution and can be recycled environmentally, but it is difficult to effectively control the crosslinking structure that shows the fluid cohesion of acrylic resin. In case of the touch test, the pressure-sensitive adhesive may be buried as well as the width of the use temperature is narrow.

As the level of culture increases, the demand for removable adhesives that can be attached and detached is increasing. The adhesive strength of the conventional acrylic pressure-sensitive adhesive was tested according to ASTM D 1002. The adhesive strength showed good values of 500-800 gf / 25 mm when the adhesive strength was weak and 800-1,000 gf / 25 mm when the steel adhesive was used. . Although the adhesive strength is good, when the release paper (liner) coated with a silicone resin is removed, attached to the adherend, and then detached after 3 days, the adhesive is transferred to the adherend and contaminated.

In the present invention, using a polyurethane composition crosslinked by light, problems such as contamination or damage of the adhered surface, transfer of the adhesive to the adhered surface, lowering of adhesive force, shrinkage of the adhesive, poor adhesion and desorption, etc. Has improved dramatically. Another object of the present invention is to provide a pressure-sensitive adhesive that can be reused many times when the coated surface is washed with water even if the film coated with the adhesive is contaminated with foreign matter such as dust and the adhesive strength is reduced. The object of the invention as described above is achieved by appropriately mixing a photopolymerizable polyurethane resin, a reactive monomer, a silicone composite, a photoinitiator and the like. The objects, advantages and features of the present invention will become more apparent from the following detailed description and examples.

It will be described in detail with reference to the embodiment of the present invention. The method for producing a pressure-sensitive adhesive material using a photopolymerizable polyurethane resin includes (1) corona discharge on the front and rear surfaces of non-hydrophilic adhesive base materials such as polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and synthetic paper. Surface treatment; (2) 34.2 to 40.5% by weight of vinyl monomer containing at least two or more double bonds, 5.2 to 9.0% by weight of a silicone composite having a double bond, 0.1 to 0.3% by weight of a photopolymerization initiator and a residual urethane-based oligomer having a double bond at the end; A pressure-sensitive adhesive layer coating step of mixing and applying to the rear surface of the attachment base material; (3) a pressing step of pressing the transparent release paper of the surface roughness 0.05-0.8s; And (4) irradiating UV-rays of 200-400 nm wavelength to a light amount of 500-5,000 mJ / cm 2 on the attached base material to which the transparent release paper is attached to photopolymerize. In the invention as described above, the pressure-sensitive adhesive layer is formed by forming the pressure-sensitive adhesive layer and pasting the release paper thereon.

The surface treatment step of (1) is a corona by applying a voltage of 1-40 KV instantaneously to the front and rear of the non-hydrophilic adhesive base such as polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), synthetic paper, etc. Corona surface treatment is a technology that improves the surface properties by discharging the high frequency and high voltage supplied by high frequency power to the surface of polyolefin film, paper, metal, etc. to improve the properties of the surface. By the treatment, the wettability can be improved by synergistic effects of physical improvement and chemical improvement of the discharge itself. Chemical surface modification is achieved by the collision of high-energy electrons or ions to produce radicals or ions on the surface of plastics, and the reaction of ozone, oxygen, nitrogen, and moisture in the surroundings. As the adhesive base material, all papers, textiles, films and the like can be used, but non-hydrophilic polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), synthetic paper, and the like are preferable. Since the adhesion of printing ink is poor due to the stability, it is preferable to increase the printability by performing corona surface treatment. At this time, the surface energy should be 40-50 dyne so that there is no problem in printability, and the back side of the attachment substrate should also be corona-treated so that it can be adhered well to the adhesive layer formed by the subsequent process.

The step of applying the pressure-sensitive adhesive layer of (2) is a step of applying a pressure-sensitive adhesive material to form an adhesive, the pressure-sensitive adhesive material is a vinyl monomer 34.2-40.5% by weight of at least two or more double bonds, silicone composite having a double bond 5.2-9.0 It is obtained by mixing the urethane oligomer which has a double bond at the terminal as a weight%, 0.1-0.3 weight% of photoinitiators, and remainder, and consists of this adhesive raw material as coating on the back surface of the said base material. Application to the attachment substrate may be applied to known coating methods. Knife coating may be used for the coating method, and coating methods and coating machines used for coating are well known to those skilled in the art. As used herein, the term "adhesive raw material" means a material coated on an adherent substrate as a raw material for forming a pressure-sensitive adhesive in a subsequent reaction step.

Urethane-based oligomer in the raw material has a large number of urethane bonds (-NHCOO-) in the molecular chain, and has a double bond (-C = C-) that can react with ultraviolet rays at the end of the molecule. First, isocyanate (-NCO) and glycol It is prepared by reacting (-OH) with a vinyl or acrylic monomer having a double bond (-C = C-). Isocyanates that can be used for the synthesis include tolylenedisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), and the like, and glycols include ethylene glycol (EG), propylene glycol (PG), 1 , 6-hexanediol (1,6-HD), polyethylene glycol (PEG), polypropylene glycol (PPG) and the like, and the vinyl monomers are glycerin monoallyl ether (GMDAE), pentaerythritol diallyl ether (PEDAE), trimethyl Olpropanediallyl ether (TMPDAE) and the like. Synthesis of polyurethane oligomer is carried out at 60-80 ° C with a glycol having hydroxyl group (-OH) at the end of the molecule and a compound having isocyanate group (-NCO) at the end of the molecule at a molar ratio of 1 / 1.2. After adding the catalyst and reacting for 5-6 hours, the vinyl monomer having a double bond in the molecular chain was added in an equivalent ratio, and then the mixture was added at 70-80 ° C. under a tertiary amine catalyst such as triethylamine (TEA). It is made to react for 4 hours. The molecular weight of the compound is 5,00 to 3,000 having a long chain structure, it can be used in the remaining amount except the content of the above components, preferably the amount is 50.2-60.5% by weight of the total composition. If the amount of the urethane-based oligomer is used less than 50.2% by weight may cause a problem that the adhesive strength is lowered, and when the amount of the urethane-based oligomer exceeds 60.5% by weight, the toughness of the pressure-sensitive adhesive layer is improved but the stiffness is too high Can be. As the urethane oligomer, PU-330 (product of Miwon Corp.), PU-256 (product of Miwon Corp.), PU-610 (product of Miwon Corp.), PU-340 (product of Miwon Corp.) and the like can be used.

Vinyl monomers are those containing two or more reactive double bonds in the molecular chain and are low molecular weight compounds having a molecular weight of 100 to 1000, ethylhexyl acrylate (EHA), 1,3-butylene glycol diacrylate (BGDA), 1 , 6-hexanediol diacrylate (HDDA), trimethylolpropanetriacrylate (TMPTA), neopentylglycol diacrylate (NPGDA) can be used, and the distance between the reactors and branched to increase flexibility It has a function of imparting adhesion. The vinyl monomer may be used in the range of 34.2-40.5 wt%. When the amount of the vinyl monomer used is less than 34.2% by weight, it is weakened due to lack of crosslinking density, and when it exceeds 40.5% by weight, brittleness may occur due to brittleness.

Silicone complexes are tertiary amine catalysts such as triethylamine (TEA) and organic acids having double bonds (-C = C-) and carboxyl groups (-COOH) and silanes with amino groups (-NH2) or epoxides at the molecular ends. It is prepared by addition and condensation reaction at 100-140 ° C. for 2-4 hours at a molar ratio of 1 / 1.1-1 / 1.2. Z-6011 (manufactured by Dow Chem Co.) and Z-6020 (manufactured by Dow Chem Co.) may be used as the aminosilane, and Z-6040 (manufactured by Dow Chem Co.) may be used as the epoxy silane. Acrylic acid (AA), methacrylic acid (MAA), etc. can be used as an organic acid. Z-6300 or the like may be used as the vinyl silane. It is used for the purpose of promoting flexibility and adhesion.

The photopolymerization initiator functions to cure the adhesive raw materials by photopolymerization by ultraviolet rays so as to exhibit adhesiveness. Such a photopolymerization initiator may be purchased and used commercially provided by leading domestic and foreign manufacturers. For example, benzoin ether or benzyl ketals can be used. Commercially available Vicure 30 (from Stauffer), Glocure 2030 (from Stauffer), trigonal 15 (from Akzo), Quantacure B1 (from Ward-blenkinsop), Irgacure 651 (Ciba-geigy), Quantacure 598 (Ciba-geigy) and the like. The photopolymerization initiator may be used in an amount of 0.1 to 0.3% by weight. When the photopolymerization initiator is used at less than 0.1% by weight, the curing time may be long and incomplete curing may occur, resulting in contamination of the adherend surface. On the contrary, when the photopolymerization initiator exceeds 0.3% by weight, the flexibility of the adhesive layer may be deteriorated. .

The pressure-sensitive adhesive raw material formed as described above is uniformly applied to a thickness of 20-50 μm on the adhesive base material. The coating thickness of the adhesive raw material may be appropriately added or subtracted depending on the type of the adherend. For example, 20-30 μm is suitable for the deposition of a smooth object having a roughness of 0.05 s or less, such as glass, and the rougher the surface roughness of the adherend, the thicker it may be applied. In addition, depending on the material of the adherend, it can be appropriately added or subtracted.

The step of pressing the release paper of (3) protects the pressure-sensitive adhesive and prevents the pressure-sensitive adhesive from sticking to the pressure-sensitive adhesive paper and attaches the release paper for convenience of use. The release paper is a transparent film in the form of polypropylene (PP) or oriented polypropylene (OPP) with a surface roughness of 0.05 to 0.8 s.

The reaction step (4) is a step of forming a pressure-sensitive adhesive layer by photopolymerization of the pressure-sensitive adhesive raw material to photopolymerization by irradiating UV-rays of 200-400nm wavelength with a light amount of 500-5,000mJ / ㎠ to the adhesive base material with a transparent release paper It consists of Irradiate the adhesive substrate to ultraviolet light, but the transparent release paper compressed as described above is directed toward the ultraviolet lamp (mercury lamp or metal lamp / wavelength 200 to 400nm) to create a condition that the ultraviolet light can be sufficiently irradiated on the adhesive raw material layer and the amount of light 500 It is effective to irradiate ultraviolet rays of 5,000mJ / cm 2, preferably 2,000-3,000mJ / cm 2. When the amount of light is less than 500 mJ / cm 2, curing by ultraviolet rays may not be sufficient, resulting in incomplete curing, resulting in contamination of the adherend. On the contrary, when the amount of light exceeds 5,000 mJ / cm 2, the pressure-sensitive adhesive molecules may be exposed to excessive amount of light. Cleavage of the chain can occur. The adhesive adhered through the above process is immediately rolled up or rolled up to a predetermined length, printed, and then Thompson processed or cut and packaged.

Hereinafter, preferred embodiments of the present invention will be described. The following examples are only intended to illustrate the invention, but not to reduce the scope of the invention.

Example 1

Polyurethane oligomer PU-330 (Mimiwon Co., Ltd.) 55.2 g, acrylic monomer 1,6-hexanediol di having an average molecular weight of 2,000 s after a corona treatment with a roughness of 0.5 s at a voltage of 5 kV on the front and rear of a polypropylene (PP) material 35.8 g of acrylate, Z-6011 and 5.2 g of a silicone compound reacted with acrylic acid (AA) at a molar ratio of 1 / 1.05 were mixed, and 0.2 g of a photopolymerization initiator Irgacure 651 (manufactured by Ciba-geigy) were applied to the back side of the attachment substrate, and After pressing the corona-treated transparent release paper was irradiated with ultraviolet light of a wavelength of 360-400nm at a light amount of 2,000mJ / ㎠ to prepare a pressure-sensitive adhesive according to the present invention.

Example 2

56.8g of urethane oligomer PU-256 (manufactured by Miwon Corporation) with an average molecular weight of 2,200 after corona treatment with a roughness of 0.6 s at a voltage of 7 kV on the front and rear of polyvinyl chloride (PVC) material, and neopentyl glycol diacryl as an acrylic monomer 35.1 g of rate, 6.2 g of a silicone composite reacting Z-6020 with methacrylic acid (MAA) at a molar ratio of 1 / 1.05, and 0.25 g of Vicure 30 (manufactured by stauffer) as a photopolymerization initiator were mixed and applied to the back of the substrate. After compressing the corona-treated transparent release paper, a pressure-sensitive adhesive deposit according to the present invention was prepared by photopolymerization by irradiating ultraviolet rays of 360-400 nm with a light amount of 2,000 mJ / cm 2.

The physical properties of the pressure-sensitive adhesive prepared according to the embodiment is shown in Table 1 compared with the conventional acrylic pressure-sensitive adhesive. The results showed superior physical properties in the important items as the adhesive as compared with the acrylic adhesive used in the past. As a result of comparing the measured values, the adhesive deposit according to the present invention was excellent in all of the adhesion resistance, peel strength, high temperature adhesive strength, low temperature adhesive strength, solvent resistance, etc., as well as increased stain resistance of the adhered surface according to the removable (removable). Taking advantage of these advantages, it can be used on labels with smooth surfaces, metal labels, vehicle glass attachments, mall window displays, tile decorations, sheet papers that can be easily removed and attached, and has excellent chemical resistance, heat resistance and cold resistance. It is widely applicable to various kinds of products such as electronic products.

Property comparison table according to the embodiment order Item unit Conventional acrylic adhesive Example 1 Example 2 Test specification One   Exterior - Translucent transparent transparent Visually 2   Viscosity cps 155 160 185 3   importance - 0.85 0.87 0.88 4 Glass transition temperature ℃ -20 -40 -45 TMA Analysis 5 Room temperature kg / cm2 10.0 12.0 13.2 ASTM D 1002 6 Peel strength kg / cm2 2.5 2.8 3.0 KSM-3728 7 High temperature adhesion kg / cm2 8.2 10.5 9.6 ASTM D 1002 8 Low temperature adhesion kg / cm2 7.3 9.8 9.6 ASTM D 1002 9 Solvent resistance % 10.0 0.5 0.4 ASTM C 581 10 Surface contamination % 8 0.1 0.2

<Test method>

1) viscosity

Spindle No. 7, rpm 2 was measured.

2) normal temperature adhesion

According to the test method of ASTM D 1002, both sides of the 25 mm horizontal, 80 mm long, 1 mm thick iron pieces were bonded with an adhesive 10 mm, dried at room temperature for 24 hours, and then measured by shear adhesion using a universal testing machine.

3) peeling strength

According to KS M 3728, two test specimens bent with a translator were bonded to 25.4 mm, and the stress was measured by applying tensile force at both ends of the test specimen.

4) high temperature adhesion

According to the test method of ASTM D 1002, both sides of the 25 mm long, 80 mm long, 1 mm thick iron pieces were bonded together with a 10 mm adhesive, dried at room temperature for 24 hours, and then the temperature of the test pieces was adjusted to 50 ° C. and measured by shear adhesion.

5) Low temperature adhesion

According to the test method of ASTM D 1002, both sides of the 25 mm long, 80 mm long, and 1 mm thick iron sheets were bonded together with a 10 mm adhesive, dried at room temperature for 24 hours, and then adjusted to a temperature of -20 ° C. using a freezer. Measured by.

6) solvent resistance

The adhesive was applied to the test piece according to ASTM C 581, completely dried, immersed in ethanol for 3 days, and then taken out to dry completely to measure the weight loss rate.

7) Surface contamination

The pressure sensitive adhesive was applied to a corona treated polyvinyl chloride (PVC) tape, dried completely, detached 30 times on a glass plate, and then the weight loss of the pressure sensitive adhesive was measured.

Using a photopolymerizable polyurethane resin, there is an effect of producing a pressure-sensitive adhesive that can be attached and detached without contaminating the surface of the adherend and providing a pressure-sensitive adhesive obtained therefrom.

Claims (4)

(1) surface-treating corona discharge on the front and rear surfaces of non-hydrophilic adhesive substrates such as polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), synthetic paper, etc .; (2) 34.2 to 40.5% by weight of vinyl monomer containing at least two or more double bonds, 5.2 to 9.0% by weight of a silicone composite having a double bond, 0.1 to 0.3% by weight of a photopolymerization initiator, and a residual urethane-based oligomer having a double bond at the end; A pressure-sensitive adhesive layer coating step of mixing and applying to the rear surface of the attachment base material; (3) a pressing step of pressing the transparent release paper of the surface roughness 0.05-0.8s; And (4) irradiating UV-rays of 200-400 nm wavelength to a light amount of 500-5,000 mJ / cm 2 on the attached base material to which the transparent release paper is attached to photopolymerize the adhesive adhesive. The method of claim 1, Process for producing a pressure sensitive adhesive using a polyurethane oligomer having a molecular weight of 2,000-2,500. The method of claim 1, Method for producing a pressure sensitive adhesive using a silicone composite synthesized by addition reaction of acrylic acid (AA) to aminosilane in a molar ratio of 1 / 1.1 Adhesive deposits obtained according to any one of claims 1 to 3.