Acrylate pressure-sensitive adhesive for silk-screen printing
By developing an acrylate pressure-sensitive adhesive for screen printing with optimized viscosity and rheological characteristics, the problems of unstable viscosity, unsuitable rheological shear viscosity and insufficient peeling force in the prior art were solved, and good adhesion, leveling and weathering properties were achieved.
Patent Information
- Application Number
- CN202411746179.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-03-25
AI Technical Summary
The viscosity of existing water-based pressure-sensitive adhesives for screen printing is unstable, the rheological shear viscosity is not suitable, the peeling force is insufficient, it is difficult to adapt to the bonding of different types of materials, and the temperature resistance and shear performance are insufficient.
A pressure-sensitive adhesive for screen printing was developed with a viscosity between 45,000-70,000 mPa·s. The rheological shear viscosity has a specific range at different shear rates, the viscosity recovery rate is above 70%, and it contains an appropriate amount of tackifying resin, defoaming agent, bactericide, rheological thickening agent and wetting agent.
This adhesive has good adhesion, leveling, defoaming and weathering properties, is suitable for high and low surface energy interfaces, and has no wire drawing phenomenon. It is suitable for bonding of different types of materials, providing excellent peeling force and temperature resistance to shearing.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of pressure-sensitive adhesives, in particular to an acrylic pressure-sensitive adhesive for screen printing. Background Art
[0002] Screen printing is a popular contact printing method because of the relative simplicity of the printing process and equipment, and the wide variety of surfaces that can be printed using this method. The screen printing process first involves making a stencil on a screen that is used to define the pattern, text, image, etc. to be printed on a specific surface. Once the screen is prepared, a pressure-sensitive adhesive is squeezed through the open areas of the stencil screen to transfer the pattern or image to that surface. As a final step, the fluid must be dried or otherwise fixed to prevent deformation and maintain the integrity of the printed pattern or image.
[0003] Screen printing is unique among other printing methods because it can be used to deliver relatively thick films of fluid, ranging from 8 microns to over 30 microns. This thick coating capability makes screen printing an ideal method for applying discrete patterns of adhesives. Adhesive materials, especially pressure sensitive adhesives, generally only demonstrate their high internal strength and desirable properties of clean removal from adherends when applied or printed at sufficient thickness.
[0004] Screen printable fluids, including adhesives, must have a specific balance of rheological properties that allow for adequate fluid flow (thixotropy - shear thinning) when extruded through the screen during the printing process and adequate viscosity recovery (anti-sagging - viscosity recovery) to prevent smudging or soaking of the printed pattern. This rheological property can be characterized by the rheological shear viscosity of the printing fluid. Viscosity is generally defined as the relative resistance of a printing fluid to continued shear or flow. When the viscosity of a screen printing fluid is too low, excessive flow after printing can result in poor image resolution. On the other hand, a printing fluid with too high a viscosity flows unevenly through the screen, resulting in poor transfer of the image or pattern to the target surface.
[0005] The water-based pressure-sensitive adhesive for screen printing disclosed in CN103524666 is composed of polymerized monomers, initiators, emulsifiers, buffers, neutralizers, rheological agents, thickeners and deionized water, wherein the polymerized monomers are made of acrylate soft monomers, acrylate hard monomers and cross-linked monomers. The acrylate soft monomer is selected from ethyl acrylate, isooctyl acrylate, butyl acrylate or lauryl acrylate; the acrylate hard monomer is selected from methyl acrylate, vinyl acetate, methyl methacrylate or styrene; the cross-linked monomer is selected from acrylic acid, methacrylic acid, maleic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate or hydroxypropyl acrylate. The viscosity of the water-based pressure-sensitive adhesive for screen printing reaches 11000-12500cps, the 180° peel strength is 800-850g / 25mm, and there is no clogging of the mesh and no wire drawing.
[0006] The product is thickened with an alkali thickener, and has a viscosity of 11000CPS. The viscosity will inevitably be unstable during the later storage process, and the rheological shear viscosity suitable for screen printing has not been defined. The viscosity coating adaptability is not strong, and its peeling force is only 800g, and it is difficult to adapt to the bonding of different types of materials.
[0007] In this context, combined with the specific needs of the industry, there is an urgent need to develop a water-based acrylic pressure-sensitive adhesive that can be used for screen printing in various occasions. Its viscosity setting can meet different printing needs, and its peeling force on various boards is very excellent, and it also has certain resistance to heat and shear performance. Summary of the invention
[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an acrylic pressure-sensitive adhesive for screen printing.
[0009] To achieve the above object, the technical solution adopted by the present invention is: an acrylic pressure-sensitive adhesive for screen printing, the viscosity of the adhesive is between 45000-70000 mPa·s, and the rheological shear viscosity at different shear rates is as follows:
[0010] 1) In 1S -1 The rheological shear viscosity range is 100-150 Pa·s;
[0011] 2) In 10S -1 The rheological shear viscosity range is 20-30 Pa·s, and the viscosity recovery rate is above 70% at this shear rate;
[0012] 3) In 16S -1 The rheological shear viscosity range is 15-20 Pa·s;
[0013] 4) In 21S -1 The rheological shear viscosity range is 10-15 Pa·s.
[0014] As a specific implementation manner, the raw materials of the adhesive include, by weight percentage: 90-95% of acrylic pressure-sensitive adhesive latex, 3-8% of tackifying resin, 0.15-0.3% of defoaming agent, 0.1%-0.35% of bactericide, 1-3% of rheological thickener and 0.05-0.35% of wetting agent, wherein the acrylic pressure-sensitive adhesive latex has a solid content of 60%±1%, a viscosity of 500-2500cps, a pH of 7.0-8.0, and a glass transition temperature of -45 to -38°C.
[0015] As a specific implementation, the tackifying resin uses a water-based rosin tackifying resin, and its softening point is between 130°C and 150°C.
[0016] As a specific implementation, the fungicide uses 1,2-benzisothiazolin-3-one.
[0017] As a specific implementation, the wetting agent is any one or more of Dow Chemical NP-10, NP-20, NP-30, and NP-40.
[0018] As a specific implementation, the thickener is a high molecular weight water-based polyurethane ester thickener.
[0019] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the acrylic pressure-sensitive adhesive for screen printing of the present invention controls the proportion of each component so that the obtained adhesive has good adhesion to high and low surface energy interfaces, good leveling and defoaming properties, good weather resistance, no drawing phenomenon, no solvent, and no toxicity, and is a preferred adhesive for screen printing. DETAILED DESCRIPTION
[0020] The technical solution of the present invention is further described below in conjunction with specific embodiments.
[0021] The following provides an acrylic pressure-sensitive adhesive for screen printing, the viscosity of the adhesive is between 45000-70000 mPa·s, and the rheological shear viscosity at different shear rates is as follows:
[0022] 1) In 1S -1 The rheological shear viscosity range is 100-150 Pa·s;
[0023] 2) In 10S -1 The rheological shear viscosity range is 20-30 Pa·s, and the viscosity recovery rate is above 70% at this shear rate;
[0024] 3) In 16S -1 The rheological shear viscosity range is 15-20 Pa·s;
[0025] 4) In 21S -1 The rheological shear viscosity range is 10-15 Pa·s.
[0026] The raw materials of the adhesive include, by weight percentage, 90-95% of acrylic pressure-sensitive adhesive latex, 3-8% of tackifying resin, 0.15-0.3% of defoaming agent, 0.1%-0.35% of bactericide, 1-3% of rheological thickener and 0.05-0.35% of wetting agent, wherein the acrylic pressure-sensitive adhesive latex has a solid content of 60%±1%, a viscosity of 500-2500cps, a pH of 7.0-8.0 and a glass transition temperature of -45 to -38°C.
[0027] Here, the acrylic pressure-sensitive adhesive emulsion is a water-based acrylic polymer emulsion, which includes the following raw materials: commercially available pure acrylic emulsion, acetic acid acrylic emulsion, and styrene acrylic emulsion. The water-based acrylic polymer emulsion has a solid content of 60%±1%, a viscosity of 500-2500cps, a pH of 7.0-8.0, and a glass transition temperature of -45 to -38°C.
[0028] The tackifying resin adopts the conventional water-based rosin tackifying resin, with an effective content of 55%±1% and a softening point of about 130-150℃. It has good plasticity and bonding strength. It has strong resistance to high and low temperatures and aging properties. It can be used with rubber series, acrylic series, pressure-sensitive adhesive, water-based coatings, and water-based paints. It has a strong tackifying effect, greatly improves adhesion and peel strength, improves weather resistance and aging resistance, and has excellent compatibility with various latex or emulsions.
[0029] Defoaming agent: Contains one or a combination of two or more defoaming agents, the main ingredients are mineral oil and emulsified silicone oil.
[0030] Fungicide: The main ingredient is 1,2-benzisothiazolin-3-one, and the solid content is 7%-10% aqueous solution.
[0031] Thickener: Use high molecular weight water-based polyurethane ester thickener with an effective content of about 50%.
[0032] The wetting agent is selected from at least one of Dow Chemical NP-10, NP-20, NP-30, and NP-40.
[0033] In the following embodiments,
[0034] The acrylic pressure-sensitive adhesive emulsion used is one or more of the models AC7363R, WBA206, AC8805, and AC6810 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is one or more of the models TSR-1009, TSR-1900L, TSR-1650, and TSR-1750 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd., and its softening point is 130-150°C (ring and ball method); the defoaming agent is one or two of the models Airex 901W purchased from TEGO and DF-677 produced by EASYTECH; the bactericide is G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is Viscoplus 3030 purchased from TEGO; the wetting agent is one or more of the models NP-10, NP-20, NP-30, and NP-40 purchased from Dow Chemical Company.
[0035] Example 1
[0036] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 92.65% acrylic pressure-sensitive adhesive emulsion, 5.6% water-based rosin tackifying resin, 0.2% defoamer, 0.2% bactericide, 1.3% thickener, and 0.05% wetting agent.
[0037] The acrylic pressure-sensitive adhesive emulsion used in this example is model WBA206 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is model TSR-1009 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd., and its softening point is 145°C (ring and ball method); the defoaming agent is model Airex 901W purchased from TEGO; the bactericide is model G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is model Viscoplus 3030 purchased from TEGO; and the wetting agent is model NP-10 purchased from Dow Chemical Company.
[0038] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 600 rpm at the same time. After the last batch is added, the stirring is maintained at 600 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0039] Example 2
[0040] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 91% acrylic pressure-sensitive adhesive emulsion, 7% water-based rosin tackifying resin, 0.3% defoaming agent, 0.1% bactericide, 1.5% thickener, and 0.1% wetting agent.
[0041] The acrylic pressure-sensitive adhesive emulsion used in this example is AC8805 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is TSR-1900L purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is DF-677 purchased from EASYTECH; the bactericide is G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is Viscoplus 3030 purchased from TEGO; and the wetting agent is a mixture of NP-10 and NP-20 purchased from Dow Chemical Company.
[0042] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 600 rpm at the same time. After the last batch is added, the stirring is maintained at 600 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0043] Example 3
[0044] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 94% acrylic pressure-sensitive adhesive emulsion, 3% water-based rosin tackifying resin, 0.3% defoaming agent, 0.35% bactericide, 2.0% thickener, and 0.35% wetting agent.
[0045] The acrylic pressure-sensitive adhesive emulsion used in this example is model AC6810 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is model TSR-1650 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is model Airex 901W purchased from TEGO; the bactericide is model G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is model Viscoplus 3030 purchased from TEGO; and the wetting agent is model NP-10 purchased from Dow Chemical Company.
[0046] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 700 rpm at the same time. After the last batch is added, the stirring is maintained at 700 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0047] Example 4
[0048] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 90% acrylic pressure-sensitive adhesive emulsion, 4% water-based rosin tackifying resin, 0.3% defoaming agent, 0.35% bactericide, 2.0% thickener, and 0.35% wetting agent.
[0049] The acrylic pressure-sensitive adhesive emulsion used in this example is WBA206 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is TSR-1750 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is a mixture of Airex 901W purchased from TEGO and DF-677 produced by EASYTECH; the bactericide is G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is Viscoplus 3030 purchased from TEGO; and the wetting agent is NP-40 purchased from Dow Chemical Company.
[0050] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 700 rpm at the same time. After the last batch is added, the stirring is maintained at 700 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0051] Example 5
[0052] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 95% acrylic pressure-sensitive adhesive emulsion, 3% water-based rosin tackifying resin, 0.3% defoaming agent, 0.35% bactericide, 1.0% thickener, and 0.35% wetting agent.
[0053] The acrylic pressure-sensitive adhesive emulsion used in this example is model AC7363R purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is a mixture of model TSR-1009 and TSR-1650 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is model Airex901W purchased from TEGO; the bactericide is model G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is model Viscoplus 3030 purchased from TEGO; and the wetting agent is model NP-40 purchased from Dow Chemical Company.
[0054] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 600 rpm at the same time. After the last batch is added, the stirring is maintained at 600 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0055] Comparative Example 1
[0056] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 92.65% acrylic pressure-sensitive adhesive emulsion, 5.6% water-based rosin tackifying resin, 0.2% defoamer, 0.2% bactericide, 1.3% thickener, and 0.05% wetting agent.
[0057] The acrylic pressure-sensitive adhesive emulsion used in this example is model WBA206 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is model TSR-1009 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is model Airex 901W purchased from TEGO; the bactericide is model G10 purchased from Shanghai Bite Biotechnology Co., Ltd.; the thickener is an alkaline thickener model C-167 purchased from Guangdong Zhonglianban Fine Chemical Co., Ltd.; the wetting agent is model NP-10 purchased from Dow Chemical Company.
[0058] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 600 rpm at the same time. After the last batch is added, the stirring is maintained at 600 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0059] Comparative Example 2
[0060] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 91% acrylic pressure-sensitive adhesive emulsion, 7% water-based rosin tackifying resin, 0.3% defoaming agent, 0.1% bactericide, 1.5% thickener, and 0.1% wetting agent.
[0061] The acrylic pressure-sensitive adhesive emulsion used in this example is model AC8805 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is a water-based tackifying resin emulsion with a softening point of 100°C, model TSR-5100, purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is DF-677 purchased from EASYTECH; the bactericide is model G10 purchased from Shanghai Bit Biotechnology Co., Ltd.; the thickener is model Viscoplus 3030 purchased from TEGO; and the wetting agent is a mixture of model NP-10 and NP-20 purchased from Dow Chemical Company.
[0062] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 600 rpm at the same time. After the last batch is added, the stirring is maintained at 600 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0063] Comparative Example 3
[0064] This example provides an acrylic pressure-sensitive adhesive for screen printing, the raw materials of which include, by weight percentage: 94% acrylic pressure-sensitive adhesive emulsion, 3% water-based rosin tackifying resin, 0.3% defoaming agent, 0.35% bactericide, 2.0% thickener, and 0.35% wetting agent.
[0065] The acrylic pressure-sensitive adhesive emulsion used in this example is model AC6810 purchased from Guangdong Yinyang Resin Co., Ltd.; the water-based rosin tackifying resin is model TSR-1009 purchased from Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.; the defoaming agent is model Airex 901W purchased from TEGO; the bactericide is model G10 purchased from Shanghai Bite Biotechnology Co., Ltd.; the thickener is model Viscoplus 3030 purchased from TEGO; and the wetting agent is a dioctyl sodium salt of sulfosuccinate wetting agent purchased from Solvay under model OT-75.
[0066] The preparation process of the adhesive is as follows: one or more acrylic pressure-sensitive adhesive latexes are added into a stirred reactor, stirring is started, and the speed is set to 200 rpm; water-based tackifying resin, defoaming agent, bactericide, and wetting agent are added respectively according to the addition ratio, stirred for 30 minutes, and mixed completely; the speed is set to 300 rpm, and the thickener is added into the stirred reactor in four batches at intervals of 10 minutes, and the stirring speed is gradually increased to 700 rpm at the same time. After the last batch is added, the stirring is maintained at 700 rpm for 30 minutes to obtain an acrylic pressure-sensitive adhesive for screen printing.
[0067] The formulas of the acrylic pressure-sensitive adhesives for screen printing of the above embodiments and comparative examples are shown in Table 1.
[0068] Table 1
[0069]
[0070] The adhesive sheets obtained in the above examples and comparative examples were evaluated according to the following evaluation method. The evaluation results are shown in Tables 2 and 3.
[0071] (I) Determination of glass transition temperature, loss elastic modulus and storage elastic modulus
[0072] An adhesive sheet with a thickness of 0.5 mm, a width of 10 mm, and a length of 10 mm was prepared and measured using a wide range dynamic viscoelasticity measuring apparatus (Solids Analyzer RSA-II, manufactured by Pheometric Scientific) in a share sandwich mode, at a frequency of 1.0 Hz, a measuring temperature range of -40 to 80°C, and a heating rate of 5°C / min.
[0073] (ii) Determination of loss angle at 120°C and 0.063Hz
[0074] An adhesive sheet with a thickness of 0.5 mm, a width of 10 mm, and a length of 10 mm was prepared and measured using a wide range dynamic viscoelasticity measuring apparatus (Solids Analyzer RSA-II, manufactured by Pheometric Scientific) in Frequencyscan mode at a temperature of 120° C. and a frequency range of 0.01 Hz to 10 Hz, resulting in a loss angle of 0.063 Hz.
[0075] (III) Rheological viscosity measurement
[0076] A wide range dynamic viscoelasticity measuring apparatus (Solids Analyzer RSA-II manufactured by Pheometric Scientific) was used to perform cyclic measurement for 120 s at a temperature of 25°C, 25 mm parallel aluminum plates, a gap of 1000 um, and a shear rate range of 0.1 to 100 s-1.
[0077] (IV) Three-force test
[0078] Then, an automatic coating machine was used to evenly coat it on a PET film with a thickness of 100 μm, and the dry glue thickness was controlled at 35 μm. It was then dried at 70°C for 20 minutes and then placed in an oven at 70°C for aging for 15 hours to obtain an ultra-thin high-peelable polyacrylate pressure-sensitive film.
[0079] The national standard GB4852-02 is used to measure the initial adhesion number of the pressure-sensitive film.
[0080] The initial adhesion number of the pressure-sensitive film is measured using the national standard GB2792-98.
[0081] The film holding force was measured using the national standard GB / T 4851-2014.
[0082] (V) <Screen printing test>
[0083] Place the sample on the screen printer and continue printing
[0084] Evaluate the printing appearance. If the lines are clear and the surface is smooth without bubbles, it is considered OK.
[0085] Evaluation of sustainable coating performance: Record the sustainable printing time.
[0086] Table 2 Rheological shear viscosity / DMA test results
[0087]
[0088] Table 3 Coating performance / screen printing performance
[0089]
[0090] It can be seen from Table 2 and Table 3 that, as in Comparative Example 1, when the adhesive is -1 When the rheological shear viscosity exceeds 150 Pa·s for 10S -1 When the rheological shear viscosity is less than 20Pa·s, it does not have screen printing performance. When the softening point of the tackifying resin used as the raw material of the adhesive is lower than 130°C, such as in Comparative Example 2, the 70°C temperature resistance of the product is not good. When the wetting agent is a dioctyl sodium salt of sulfosuccinate wetting agent, such as in Comparative Example 3, the continuous printing time is low.
[0091] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.
Claims
1. An acrylic pressure-sensitive adhesive for screen printing, characterized in that: The viscosity of the adhesive is between 45000-70000 mPa·s, and the rheological shear viscosity at different shear rates is as follows: 1) In 1S -1 The rheological shear viscosity range is 100-150 Pa·s; 2) In 10S -1 The rheological shear viscosity range is 20-30 Pa·s, and the viscosity recovery rate is above 70% at this shear rate; 3) In 16S -1 The rheological shear viscosity range is 15-20 Pa·s; 4) In 21S -1 The rheological shear viscosity range is 10-15 Pa·s.
2. The acrylate pressure-sensitive adhesive for screen printing according to claim 1, characterized in that: The raw materials of the adhesive include, by weight percentage, 90-95% of acrylic pressure-sensitive adhesive latex, 3-8% of tackifying resin, 0.15-0.3% of defoaming agent, 0.1%-0.35% of bactericide, 1-3% of rheological thickener and 0.05-0.35% of wetting agent, wherein the acrylic pressure-sensitive adhesive latex has a solid content of 60%±1%, a viscosity of 500-2500cps, a pH of 7.0-8.0, and a glass transition temperature of -45~-38°C.
3. The acrylate pressure-sensitive adhesive for screen printing according to claim 2, characterized in that: The tackifying resin adopts water-based rosin tackifying resin, and its softening point is between 130°C and 150°C.
4. The acrylic pressure-sensitive adhesive for screen printing according to claim 2, characterized in that: The fungicide adopts 1,2-benzisothiazolin-3-one.
5. The acrylate pressure-sensitive adhesive for screen printing according to claim 2, characterized in that: The wetting agent is any one or more of Dow Chemical NP-10, NP-20, NP-30, and NP-40.
6. The acrylic pressure-sensitive adhesive for screen printing according to claim 2, characterized in that: The thickener adopts a high molecular weight water-based polyurethane ester thickener.