阅读说明：本技术 天然橡胶接枝丙烯酸酯乳液型压敏胶、产品及其制备方法 (Natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, product and preparation method thereof ) 是由 吴博崇 于 2021-10-14 设计创作，主要内容包括：本发明公开了一种天然橡胶接枝丙烯酸酯乳液型压敏胶、产品及其制备方法,其中,该天然橡胶接枝丙烯酸酯乳液型压敏胶,包括：天然橡胶乳胶液10.25～21.1份；接枝单体0.56～2.12份,选自：甲基丙烯酸-2-乙基已酯、甲基丙烯酸丁酯、甲基丙烯酸乙酯中的一种或多种；压敏性单体11.99～23.98份,选自：丙烯酸丁酯、丙烯酸乙酯、丙烯酸乙基已酯中的一种或多种；交联单体0.1～0.2份,选自：丙烯酸或甲基丙烯酸；官能单体0.35～0.7份,选自：丙烯酸羟乙酯、甲基丙烯酸羟乙酯或丙烯酸羟丙酯中的一种或多种；增粘树脂35.78～68.69份,选自：松香、松香甘油脂、萜烯树脂、氢化松香或部分氢化松香中的一种或多种；以及水7.74～15.48份。本发明是一种低碳、节能、减排水基压敏胶,突破了水基压敏胶粘着力学性能不足的缺陷。(The invention discloses a natural rubber grafted acrylate emulsion pressure-sensitive adhesive, a product and a preparation method thereof, wherein the natural rubber grafted acrylate emulsion pressure-sensitive adhesive comprises the following components: 10.25-21.1 parts of natural rubber latex; 0.56-2.12 parts of a grafting monomer selected from: one or more of 2-ethylhexyl methacrylate, butyl methacrylate and ethyl methacrylate; 11.99-23.98 parts of pressure-sensitive monomer, which is selected from: one or more of butyl acrylate, ethyl acrylate and ethyl hexyl acrylate; 0.1-0.2 part of crosslinking monomer selected from: acrylic acid or methacrylic acid; 0.35-0.7 parts of functional monomer selected from: one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate or hydroxypropyl acrylate; 35.78-68.69 parts of tackifying resin, which is selected from: one or more of rosin, rosin glyceride, terpene resin, hydrogenated rosin or partially hydrogenated rosin; and 7.74-15.48 parts of water. The invention is a low-carbon, energy-saving and emission-reducing water-based pressure-sensitive adhesive, and overcomes the defect of insufficient mechanical property of the water-based pressure-sensitive adhesive.)

1. The natural rubber grafted acrylate emulsion type pressure-sensitive adhesive is characterized by comprising the following preparation raw materials in parts by weight:

10.25-21.1 parts of natural rubber latex;

0.56-2.12 parts of a grafting monomer, wherein the grafting monomer is selected from the following group: one or more of 2-ethylhexyl methacrylate, butyl methacrylate and ethyl methacrylate;

11.99-23.98 parts of pressure-sensitive monomer, wherein the pressure-sensitive monomer is selected from the following group: one or more of butyl acrylate, ethyl acrylate and ethyl hexyl acrylate;

0.1-0.2 part of a crosslinking monomer selected from the group consisting of: acrylic acid or methacrylic acid;

0.35-0.7 parts of functional monomer, wherein the functional monomer is selected from the following group: one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate or hydroxypropyl acrylate;

35.78-68.69 parts of tackifying resin, wherein the tackifying resin is selected from the following components: one or more of rosin, rosin glyceride, terpene resin, hydrogenated rosin or partially hydrogenated rosin; and

7.74-15.48 parts of water.

2. The natural rubber graft acrylate emulsion pressure sensitive adhesive of claim 1, wherein the preparation raw materials further comprise, in parts by weight: one or more of a cross-linking agent, an initiator and an emulsifier; preferably, the first and second electrodes are formed of a metal,

the cross-linking agent is selected from: one or more of stannous chloride, zinc acetate or stearyl erucyl; and/or the presence of a gas in the gas,

the initiator comprises: one or more of ammonium persulfate, sodium persulfate and potassium persulfate; and/or the presence of a gas in the gas,

the emulsifier comprises: one or two of sodium dodecyl diphenyl ether disulfonate or sodium hexadecylsulfonate.

3. The natural rubber graft acrylate emulsion pressure sensitive adhesive according to any one of claims 1 or 2, wherein the preparation raw materials further comprise: one or more of an antioxidant, a preservative, a residual monomer treatment or a neutralizing agent; preferably, the first and second electrodes are formed of a metal,

the antioxidant is selected from: one or more of cresol, dicyclopentadiene copolymer, dibutyl hydroxy toluene and tert-butyl hydroquinone; and/or the presence of a gas in the gas,

the preservative is selected from: one or more of sorbic acid, potassium sorbate, benzoic acid, sodium benzoate and calcium propionate; and/or the presence of a gas in the gas,

the residual monomer treatment agent is selected from: one or more of tert-butyl hydroperoxide, ammonium persulfate, sodium persulfate and potassium persulfate; and/or the presence of a gas in the gas,

the neutralizer is ammonia water.

4. The natural rubber graft acrylate emulsion pressure-sensitive adhesive according to claim 3, wherein the crosslinking agent is 0.05 to 0.3 parts by weight; 0.06-0.12 part of an initiator; 0.2-0.4 part of an emulsifier; and/or the presence of a gas in the gas,

0.05-0.3 part of antioxidant; 0.02-0.15 part of preservative; 0.01-0.02 part of residual monomer treating agent; and 0.05-0.1 part of a neutralizing agent.

5. A method for preparing the natural rubber graft acrylate emulsion type pressure sensitive adhesive according to any one of claims 1 to 4, comprising the steps of:

step 1: weighing natural rubber emulsion, a grafting monomer and a cross-linking agent, injecting the natural rubber emulsion, the grafting monomer and the cross-linking agent into a first container, mixing and stirring, heating to a first reaction temperature, keeping the temperature and stirring to obtain a backing material; preferably, the first reaction temperature is between 50 ℃ and 55 ℃;

step 2: weighing a pressure-sensitive monomer, a crosslinking monomer, a functional monomer, an emulsifier, an initiator and water, injecting into a second container, mixing and stirring to obtain a mixed monomer emulsion;

and step 3: injecting part of the mixed monomer emulsion into the first container, mixing and stirring with the bedding materials, continuously heating to a second reaction temperature, keeping the temperature, and stirring to obtain a graft polymerization bedding material; preferably, the second reaction temperature is between 73 ℃ and 75 ℃;

and 4, step 4: adding an initiator into the first container, and heating to a third reaction temperature to obtain a graft polymerization seed emulsion; preferably, the third reaction temperature is between 83 ℃ and 85 ℃;

and 5: injecting the other part of the mixed monomer into the first container for graft titration polymerization reaction and heat preservation to obtain the natural rubber graft acrylate emulsion type pressure-sensitive adhesive;

wherein a tackifying resin is added in the step 1 or after the step 5.

6. The method according to claim 5, wherein an antioxidant and/or a preservative are further added in step 1; and/or the presence of a gas in the gas,

in the step 5, a residual monomer treating agent and/or a neutralizing agent are/is added; and/or the presence of a gas in the gas,

in the step 3, the part of the mixed monomer emulsion accounts for 5 to 15 percent of the total mass of the mixed monomer emulsion in the second container; and/or the presence of a gas in the gas,

in the step 5, the titration time of the graft titration polymerization reaction is 1h to 3h, and the heat preservation time is 0.5h to 2 h.

7. A pressure-sensitive adhesive product, which is characterized by comprising a medium layer and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer contains the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive as claimed in claims 1 to 3; or, the pressure-sensitive adhesive layer also has the natural rubber graft acrylate emulsion type pressure-sensitive adhesive obtained by the preparation method as described in claim 4 or 5.

8. The pressure-sensitive adhesive product of claim 7, wherein the dielectric layer comprises: a composite of one or more of paper, plastic film, textile or metal foil; and/or the presence of a gas in the gas,

the thickness of the pressure-sensitive adhesive layer is between 10 and 50 μm; preferably, the thickness is between 25 μm and 50 μm; and/or the presence of a gas in the gas,

the pressure-sensitive adhesive layer is arranged on the two sides of the dielectric layer.

9. The pressure-sensitive adhesive product of claim 8, wherein the paper comprises: one or more of cotton paper, kraft paper, japanese paper, crepe paper, beauty paper, base paper for trademark paper, base paper for photo, glassine paper or wallpaper;

the plastic film includes: one or more of a PP polypropylene film, a PE polyethylene film, a PVC polyvinyl chloride film, a PET polyester film, a PLA degradable film, a PBAT-PLA degradable film, a PBS degradable film or a PPC degradable film;

the textile fabric comprises one or more of cotton cloth, chemical fiber cloth, non-woven fabric, acetate fiber cloth or glass fiber cloth.

10. A method for preparing a pressure sensitive adhesive product according to any of claims 7 to 9, comprising the steps of: coating the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive on the medium layer, and drying to form the pressure-sensitive adhesive layer; preferably, the thickness of the coating is between 10 μm and 50 μm, the drying temperature is between 100 ℃ and 110 ℃, and the drying time is between 2min and 5 min.

Technical Field

The invention relates to a pressure-sensitive adhesive, in particular to a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, a product and a preparation method thereof.

Background

In pressure-sensitive adhesive tape products, water-based acrylic pressure-sensitive adhesives, solvent-based rubber series pressure-sensitive adhesives and pressure-sensitive hot melt adhesives are classified according to the use condition of the pressure-sensitive adhesives, the current domestic market demand is more than 1000 million tons every year, and the annual output value is about 1500 million yuan.

The emulsion type acrylate pressure-sensitive adhesive (also called aqueous pressure-sensitive adhesive) has low production cost, conforms to the national VOC emission standard and is environment-friendly, so that the emulsion type acrylate pressure-sensitive adhesive is widely concerned and used by the pressure-sensitive adhesive tape product industry, and the market share is more than 50 percent; however, the inherent structure has the defects of hard adhesive mechanical property, soft adhesive sealing property, initial adhesion force of <18 Ball Tack, adhesive force of <1100gf/25mm, and holding adhesion force of <24h/25mm, and the like, so the adhesive tape product is difficult to meet the requirement and is rejected in the application of high value-added adhesive tape products in the high-tech industrial field.

The solvent type rubber series pressure-sensitive adhesive has flexible pressure-sensitive adhesive mechanical property, and good initial viscosity and creeping property, and is beneficial to wide application of pressure-sensitive adhesive tape products in coating and processing. However, as the product property belongs to a dangerous product, the pollution of waste gas emission is large (the solid content is low, the content of VOC organic solvent is 60-75%), and the storage has a large potential safety hazard; the search for a pressure sensitive adhesive with "oil to water" properties is becoming the largest demand in the adhesive tape industry.

In the aspect of solvent type acrylate pressure-sensitive adhesives, the problems of large energy consumption and high production cost of solvent type rubber series pressure-sensitive adhesives can be shared since the application, but the structure essence belongs to dangerous goods, and in particular, in recent years, the problems of environmental protection safety supervision regulations, strict execution and control of regulations and the like cause huge pressure and troubles in the production and application of pressure-sensitive adhesive tape products. The emulsion pressure-sensitive adhesive with the property of changing oil into water will become the inevitable development trend and demand of pressure-sensitive adhesive tape products.

In addition, in order to improve the initial adhesion, adhesive force and permanent adhesion of the emulsion acrylate pressure-sensitive adhesive, the raw material formula of the pressure-sensitive adhesive generally needs to use a higher rubber content (30-50% by mass), and since the rubber has higher viscosity, the problem of uneven polymerization is brought when the rubber is subjected to modified polymerization, thereby affecting the performance of the emulsion pressure-sensitive adhesive.

Disclosure of Invention

The invention provides a natural rubber grafted acrylate emulsion pressure-sensitive adhesive, aiming at the defects of insufficient pressure-sensitive adhesive mechanical properties of emulsion acrylate pressure-sensitive adhesive, such as initial viscosity of No. 18 Ball Tack, adhesive force of No. 1100g/25mm, and constant viscosity of No. 24h/25mm, and the like in the prior art, and the preparation raw materials comprise the following components in parts by weight: 10.25-21.1 parts of natural rubber latex; 0.56-2.12 parts of a grafting monomer, wherein the grafting monomer is selected from the following group: one or more of 2-ethylhexyl methacrylate, butyl methacrylate and ethyl methacrylate; 11.99-23.98 parts of pressure-sensitive monomer, wherein the pressure-sensitive monomer is selected from the following components: one or more of butyl acrylate, ethyl acrylate and ethyl hexyl acrylate; 0.1-0.2 part of crosslinking monomer, wherein the crosslinking monomer is selected from the following monomers: acrylic acid or methacrylic acid; 0.35-0.7 parts of functional monomer, wherein the functional monomer is selected from the following group: one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate or hydroxypropyl acrylate; 35.78-68.69 parts of tackifying resin, wherein the tackifying resin is selected from the following components: one or more of rosin, rosin glyceride, terpene resin, hydrogenated rosin or partially hydrogenated rosin; and 7.74-15.48 parts of water.

In some embodiments, the preparation raw materials further comprise, by weight: one or more of a cross-linking agent, an initiator and an emulsifier; preferably, the crosslinking agent is selected from: one or more of stannous chloride, zinc acetate or stearyl erucyl; and/or, the initiator comprises: one or more of ammonium persulfate, sodium persulfate and potassium persulfate; and/or, the emulsifier comprises: one or two of sodium dodecyl diphenyl ether disulfonate or sodium hexadecylsulfonate.

In some embodiments, the preparation feedstock further comprises: one or more of an antioxidant, a preservative, a residual monomer treatment or a neutralizing agent; preferably, the antioxidant is selected from: one or more of cresol, dicyclopentadiene copolymer, dibutyl hydroxy toluene and tert-butyl hydroquinone; and/or, the preservative is selected from: one or more of sorbic acid, potassium sorbate, benzoic acid, sodium benzoate and calcium propionate; and/or, the residual monomer treatment agent is selected from: one or more of tert-butyl hydroperoxide, ammonium persulfate, sodium persulfate and potassium persulfate; and/or the neutralizing agent is ammonia water.

In some embodiments, 0.05 to 0.3 parts by weight of a crosslinking agent; 0.06-0.12 part of an initiator; 0.2-0.4 part of an emulsifier; and/or 0.05-0.3 part of antioxidant; 0.02-0.15 part of preservative; 0.01-0.02 part of residual monomer treating agent; 0.05-0.1 part of neutralizing agent.

The invention also provides a preparation method of the natural rubber grafted acrylate emulsion pressure-sensitive adhesive, which comprises the following steps: step 1: weighing natural rubber emulsion, a grafting monomer and a cross-linking agent, injecting the natural rubber emulsion, the grafting monomer and the cross-linking agent into a first container, mixing and stirring, heating to a first reaction temperature, keeping the temperature and stirring to obtain a backing material; preferably, the first reaction temperature is between 50 ℃ and 55 ℃; step 2: weighing a pressure-sensitive monomer, a crosslinking monomer, a functional monomer, an emulsifier, an initiator and water, injecting into a second container, mixing and stirring to obtain a mixed monomer emulsion; and step 3: injecting part of the mixed monomer emulsion into a first container, mixing and stirring with the bedding materials, and continuously heating to a second reaction temperature, keeping the temperature and stirring to obtain a graft polymerization bedding material; preferably, the second reaction temperature is between 73 ℃ and 75 ℃; and 4, step 4: adding an initiator into the first container, and heating to a third reaction temperature to obtain a graft polymerization seed emulsion; preferably, the third reaction temperature is between 83 ℃ and 85 ℃; and 5: injecting the other part of the mixed monomer into a first container for graft titration polymerization reaction and heat preservation to obtain the natural rubber graft acrylate emulsion pressure-sensitive adhesive; wherein the tackifying resin is added in step 1 or after step 5.

In some embodiments, an antioxidant and/or a preservative are also added in step 1; and/or, in the step 5, a residual monomer treating agent and/or a neutralizing agent are added; and/or, in the step 3, part of the mixed monomer emulsion accounts for 5 to 15 percent of the total mass of the mixed monomer emulsion in the second container; and/or in the step 5, the titration time of the graft titration polymerization reaction is 1-3 h, and the heat preservation time is 0.5-2 h.

The invention also provides a pressure-sensitive adhesive product, which comprises a medium layer and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer contains the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive; or the pressure-sensitive adhesive layer also comprises the natural rubber grafted acrylate emulsion pressure-sensitive adhesive obtained by the preparation method.

In some embodiments, the dielectric layer comprises: a composite of one or more of paper, plastic film, textile or metal foil; and/or the thickness of the pressure-sensitive adhesive layer is between 10 and 50 μm; preferably, the thickness is between 25 μm and 50 μm; and/or the double sides of the medium layer are provided with pressure-sensitive adhesive layers.

In some embodiments, the paper grades comprise: one or more of cotton paper, kraft paper, japanese paper, crepe paper, beauty paper, base paper for trademark paper, base paper for photo, glassine paper or wallpaper; the plastic film includes: one or more of a PP polypropylene film, a PE polyethylene film, a PVC polyvinyl chloride film, a PET polyester film, a PLA degradable film, a PBAT-PLA degradable film, a PBS degradable film or a PPC degradable film; the textile fabric comprises one or more of cotton cloth, chemical fiber cloth, non-woven fabric, acetate fiber cloth or glass fiber cloth.

In another aspect, the present invention further provides a method for preparing a pressure-sensitive adhesive product, comprising the steps of: coating a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive on the medium layer, and drying to form a pressure-sensitive adhesive layer; preferably, the thickness of the coating is between 10 μm and 50 μm, the drying temperature is between 100 ℃ and 110 ℃, and the drying time is between 2min and 5 min.

Compared with the prior art, the invention has the beneficial technical effects that:

1. the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive has excellent pressure-sensitive adhesive mechanical property, the initial adhesive force is greater than No. 20 Ball Tack, the adhesive force is 1100-1480 gf/25mm, and the permanent adhesive force is 24h/1kg, so that the defect of insufficient adhesive mechanical property of the emulsion type pressure-sensitive adhesive (water-based pressure-sensitive adhesive) is overcome.

2. The invention belongs to a pressure-sensitive adhesive with the property of changing oil into water, which is a low-carbon, energy-saving and emission-reducing water-based pressure-sensitive adhesive product prepared by applying natural rubber and an acrylic acid monomer and performing graft polymerization by an emulsion polymerization method, and meets the requirement of strict control on VOC emission in two national environmental protection standards of 'emission standards of coating, ink and adhesive industry atmospheric pollutants' (solicited proposal) 'emission control standards of volatile organic solvent inorganization)', which are issued by the national environmental protection ministry; the pressure sensitive adhesive tape product with oil changed into water becomes the development direction of the pressure sensitive adhesive tape industry.

3. The invention provides a pressure-sensitive adhesive with low natural rubber content and a preparation method thereof, which can be used for preparing a uniformly crosslinked polymer, ensuring excellent pressure-sensitive adhesive mechanical property, reducing polymerization reaction time and greatly improving production efficiency.

4. The natural rubber grafted acrylate emulsion pressure-sensitive adhesive is mainly used as an environment-friendly substitute product, and can generate remarkable economic benefit when being applied.

5. The natural rubber grafted acrylate emulsion type pressure-sensitive adhesive has wide application temperature range, particularly has excellent low temperature resistance, and still maintains excellent pressure-sensitive adhesive mechanical property at the application temperature range of minus 35 ℃.

Drawings

FIG. 1 is a schematic representation of the steps of a process for preparing a natural rubber graft acrylate emulsion type pressure sensitive adhesive in example 3 of the present invention;

FIG. 2 is a diagram showing the steps of a method for preparing a natural rubber graft acrylate emulsion type pressure sensitive adhesive in example 4 of the present invention.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

The invention relates to a test for pressure-sensitive adhesives, wherein the solid content is determined as follows: putting 5-10 g of the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive provided by the invention into a scale with peeled and weighed weight, continuously drying for 3h in a constant-temperature drying box at 105-110 ℃, and cooling to obtain the solid content;

measurement of viscosity: testing with NDJ-1 type rotational viscometer under the test conditions of 25 ℃ and 60r/min of a No. 3 rotor;

and (3) testing initial adhesion: according to GB 4852-1984;

180 ° peel adhesion test: measured according to GB 2729-1988;

and (3) permanent adhesion testing: according to GB 4851-1988.

The invention has the technical conception that the natural rubber emulsion is selected as the raw material (the main component is cis-1, 4-polyisoprene), on one hand, the flexibility of the natural rubber molecular chain is utilized, on the other hand, the affinity of the natural rubber emulsion and the solvent water is utilized, so that homogeneous water system emulsion is easily formed, and the polymerization reaction is further promoted; the invention also grafts the elastic functional group on the molecular chain of the natural rubber through the grafting monomer, further improve the elastic property of the molecular chain of the natural rubber; the polymer is endowed with pressure-sensitive characteristics by grafting a pressure-sensitive monomer on the molecular chain of the natural rubber; by grafting hydrophilic groups on the polymer through the functional monomer, the hydrophilicity of the polymer is increased, and the adhesive force and the permanent adhesive force of the pressure-sensitive adhesive are improved; the crosslinking monomer provides crosslinking action among molecular chains, the tackifying resin is filled among the crosslinking molecular chains to adjust the adhesive mechanical property of the pressure-sensitive adhesive, and the obtained pressure-sensitive adhesive has excellent initial adhesion, adhesive force and permanent adhesion.

Example 1

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which comprises the following raw materials in parts by weight: 10.25-21.1 parts of natural rubber emulsion, 0.56-2.12 parts of grafting monomer, 11.99-23.98 parts of pressure-sensitive monomer, 0.1-0.2 part of crosslinking monomer, 0.35-0.7 part of functional monomer, 35.78-68.69 parts of tackifying resin, 0.05-0.3 part of crosslinking agent, 0.06-0.12 part of initiator and 0.2-0.4 part of emulsifier; 7.74-15.48 parts of water.

Wherein the grafting monomer is acrylate containing elastic functional group, has the characteristics of acrylic acid and elastomer, and is represented by the chemical formula R-O-R', wherein R is acrylic group (CH)₂CH-CO-or CH₃And the-CH-CO-, R 'is alkyl with the carbon chain length of 2-8, and C-C in R and double bonds on a molecular chain in the natural rubber perform addition reaction, so that an elastic functional group-R' is grafted on the molecular chain of the natural rubber, and the effect of increasing the elasticity of the natural rubber is achieved. The grafting monomers of the invention are selected from: 2-ethylhexyl methacrylate, butyl methacrylate and ethyl methacrylate. In this embodiment, 2-ethylhexyl methacrylate is preferred, and 2-ethylhexyl methacrylate has a better elastic modulus and more flexible properties, unlike methyl methacrylate, which is harder in properties, affecting the mechanical and physical properties of the present invention.

The pressure-sensitive monomer is acrylate capable of bringing pressure-sensitive characteristics, and is selected from the following group: one or more of butyl acrylate, ethyl acrylate or 2-ethylhexyl acrylate (commonly known as octyl acrylate). In this example, butyl acrylate is preferred because homopolymers of these pressure sensitive monomers, homogeneously polymerized by the emulsion polymerization process, have differential pressure sensitive adhesive mechanical properties, such as the adhesive mechanical properties of polybutyl acrylate, adhesion >6N/25mm, adhesion of poly-2-ethylhexyl acrylate <4.5N/25mm, and adhesion of polyethyl acrylate <1.5N/25 mm; among them, butyl acrylate is the most excellent in adhesion and is therefore listed as a preferable pressure-sensitive monomer.

The crosslinking monomer is a monomer for providing crosslinking between molecular chains, and comprises acrylic acid or methacrylic acid, wherein C ═ C in the acrylic acid or the methacrylic acid is used for realizing crosslinking between the molecular chains; acrylic acid is preferred in this embodiment.

The functional monomer is acrylate having acrylic group and hydrophilic group, wherein the hydrophilic group comprises hydroxyl group (-OH), amino group (-NH)₂) Or carboxyl (-COOH), represented by the formula R-O-R ", wherein R is acrylic group (CH)₂CH-CO-or CH₃-CH ═ CH-CO-), and C ═ C in R is subjected to addition reaction with double bonds on the molecular chain in the natural rubber, thereby grafting the hydrophilic group-R "on the molecular chain of the natural rubber. The functional monomers of the present invention are selected from: one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 2-hydroxyethyl methacrylate;

in this embodiment, 2-hydroxyethyl acrylate is preferred; the reason is that the 2-hydroxyethyl acrylate, the 2-hydroxypropyl acrylate and the 2-hydroxyethyl methacrylate functional monomers have different pressure-sensitive mechanical property expressions for a pressure-sensitive adhesive system formed by the final copolymer; wherein, the methacrylic acid-2-hydroxyethyl ester homopolymer has higher hardness and is not beneficial to the application of products with initial viscous force and creeping performance requirements; however, the homopolymer of 2-hydroxypropyl acrylate, although having excellent initial tack and creeping characteristics, has not only the strength and adhesion strength of the copolymer system formed by graft polymerization of the auxiliary multi-component monomer and the natural rubber, but also the excellent overall performance of 2-hydroxyethyl acrylate, i.e., 2-hydroxyethyl acrylate.

The tackifying resin is used for filling and crosslinking polymer chains, can adjust or increase the mechanical property of pressure-sensitive adhesion of the pressure-sensitive adhesive, and improve the adhesive force and the permanent adhesive force of the pressure-sensitive adhesive, and comprises one or more of rosin, rosin glyceride, terpene resin, hydrogenated rosin and partially hydrogenated rosin.

Natural rubber emulsion with solid content of more than or equal to 50% is preferably prepared in the embodiment of the invention.

The cross-linking agent is selected from: one or more of stannous chloride, zinc acetate or octadecyl erucyl acyl, which is used for reinforcing the cohesive strength of the natural rubber emulsion and the viscosity of the final graft polymerization copolymer; stannous chloride is preferred in this embodiment.

The initiator is selected from: one or more of ammonium persulfate, sodium persulfate and potassium persulfate.

The emulsifier is selected from: one or two of sodium dodecyl diphenyl ether disulfonate or sodium hexadecylsulfonate.

Example 2

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from the following raw materials in a similar manner as in embodiment 1, except that the pressure-sensitive adhesive of the embodiment is prepared from the following raw materials in an adding manner: one or more of an antioxidant, a preservative, a residual monomer treatment or a neutralizing agent; the preferred addition of these additives is based on two manufacturing process requirements: firstly, the residual monomer treating agent is added to promote the conversion polymerization of the residual monomer of the acrylate emulsion and the rudiment copolymer to finally form the copolymer, the pH value (Ph value) of the copolymer is 3-4, the copolymer is moderate in acidity and corrosive, and the neutralizing agent is added to adjust the Ph value to 7.0-8.5, so that the copolymer is beneficial to coating. Secondly, the components of the invention contain natural rubber latex, antioxidant is added to enhance the oxidation resistance of the natural rubber latex, and preservative is added to play the role of corrosion prevention of the natural rubber latex.

Preferably, the addition amount according to the parts by weight is as follows: 0.05-0.3 part of antioxidant; 0.02-0.15 part of preservative; 0.01-0.02 part of residual monomer treating agent; 0.05-0.1 part of neutralizing agent.

In some embodiments, the antioxidant is selected from: one or more of cresol, dicyclopentadiene copolymer, dibutyl hydroxy toluene and tert-butyl hydroquinone; cresol and dicyclopentadiene copolymers are preferred in this embodiment; the preservative is selected from: one or more of sorbic acid, potassium sorbate, benzoic acid, sodium benzoate and calcium propionate; sorbic acid is preferred in this embodiment; the residual monomer treatment is selected from: one or more of tert-butyl hydroperoxide, ammonium persulfate, sodium persulfate and potassium persulfate; preferably tert-butyl hydroperoxide in this embodiment; in this example, the neutralizing agent is ammonia.

Example 3

This example provides a method for preparing a natural rubber grafted acrylate emulsion pressure-sensitive adhesive, wherein the raw materials used in example 1 are shown in fig. 1, and the method includes the following steps:

step S101: weighing natural rubber emulsion, a grafting monomer and a cross-linking agent, injecting the natural rubber emulsion, the grafting monomer and the cross-linking agent into a first container, mixing and stirring, heating to a first reaction temperature of 50-55 ℃, and keeping the temperature and stirring to obtain a backing material;

step S102: weighing a pressure-sensitive monomer, a crosslinking monomer, a functional monomer, an emulsifier, an initiator and deionized water, injecting into a second container, mixing and stirring to obtain a mixed monomer emulsion;

step S103: injecting part of the mixed monomer emulsion in the second container into the first container, mixing and stirring the mixed monomer emulsion with the bedding materials, and continuously heating to the second reaction temperature of 73-75 ℃, keeping the temperature and stirring to obtain a graft polymerization bedding material; preferably, the mixed monomer emulsion injected into the first container is 5% to 15% of the total mass of the mixed monomer emulsion in the second container.

The pre-emulsified mixed monomer is added in two steps: the method comprises the following steps of (1) promoting the generation of copolymerization between a backing material and a mixed monomer emulsion to form a seed emulsion of a graft polymer system; and secondly, titrating the residual mixed monomer emulsion along with the formation of a graft polymerization seed emulsion system, titrating and amplifying the gauge modulus of the final graft polymer progressively, converting the final graft polymer into a graft polymerization rudiment copolymer progressively, and stirring at a constant temperature after titration to obtain the homogeneous and stable natural rubber graft acrylate emulsion pressure-sensitive adhesive. Otherwise, the mixed monomer emulsion is frequently dissociated in the titration polymerization reaction process, cannot become a mature copolymer, and is easy to generate micelle and demulsification.

Step S104: adding an initiator into the first container, and heating to a third reaction temperature of 83-85 ℃ to obtain a graft polymerization seed emulsion;

step S105: injecting the residual mixed monomer in the second container into the first container for graft titration polymerization reaction and heat preservation, and cooling to obtain a graft copolymer; preferably, in the process of graft titration polymerization, in order to ensure homogeneous graft copolymerization of the graft copolymer, the titration speed is in the range of 1h to 3h, and is not suitable to exceed 3h, in order to avoid the increase of the viscosity of the rudiment copolymer in over polymerization to generate gel or micelle, after the graft titration polymerization reaction is finished, the heat preservation stirring is carried out for 0.5h to 2h, so that the conversion of the residual monomer can be promoted, and the graft polymerization copolymer with higher conversion rate is formed; more preferably, the titration time of the graft titration polymerization reaction is 2h to 2.5h, and the holding time is 1h to 1.5 h;

step S106: and adding tackifying resin into the first container, mixing and stirring to obtain the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive.

The invention preferably adopts three different reaction temperatures to ensure the stability of the micelle molecular structure of graft polymerization of the backing material and the mixed monomer, wherein the three different reaction temperatures have the following functions: the first reaction temperature is 50-55 ℃ and is used for heating and stirring the backing material to ensure the fusibility of the natural rubber emulsion and the grafting monomer, so as to avoid the loss of the grafting monomer in an over-high temperature state and the generation of micelle or gel phenomenon; the second reaction temperature is between 73 ℃ and 75 ℃, in gradual temperature rise, the backing material and the acrylic mixed monomer emulsion become stable reaction groups, the initiator plays a role to generate heat, and the temperature rises to 83 ℃ to 85 ℃, so that the seed emulsion of the graft polymerization reaction is formed; the third reaction temperature is between 83 ℃ and 85 ℃, and sufficient heat is provided for the quantitative expansion of the seed emulsion in the mixed monomer emulsion progressive titration polymerization reaction scale, so that the transfer or residue of the mixed monomer is reduced.

Example 4

The invention provides another preparation method of a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, wherein the preparation raw materials in the embodiment 1 are adopted, and as shown in figure 2, the preparation method comprises the following steps:

step S201: weighing natural rubber emulsion, a grafting monomer, a cross-linking agent and tackifying resin, injecting the natural rubber emulsion, the grafting monomer, the cross-linking agent and the tackifying resin into a first container, mixing and stirring, heating to a first reaction temperature of 50-55 ℃, and keeping the temperature and stirring to obtain a backing material;

step S202: weighing a pressure-sensitive monomer, a crosslinking monomer, a functional monomer, an emulsifier, an initiator and deionized water, injecting into a second container, mixing and stirring to obtain a mixed monomer emulsion;

step S203: injecting part of the mixed monomer emulsion in the second container into the first container, mixing and stirring the mixed monomer emulsion with the bedding materials, and continuously heating to the second reaction temperature of 73-75 ℃, keeping the temperature and stirring to obtain a graft polymerization bedding material; preferably, the mixed monomer emulsion injected into the first container is 5% to 15% of the total mass of the mixed monomer emulsion in the second container.

Step S204: adding an initiator into the first container, and heating to a third reaction temperature of 83-85 ℃ to obtain a graft polymerization seed emulsion;

step S205: at a fourth reaction temperature of between 81 and 83 ℃, emulsifying and titrating the residual mixed monomer in the second container, injecting the residual mixed monomer into the first container for graft titration polymerization reaction, preserving heat, and cooling to obtain the natural rubber graft acrylate emulsion pressure-sensitive adhesive; preferably, the titration time of the graft titration polymerization reaction is 1h to 3h, and the heat preservation time is 0.5h to 2h, more preferably, the titration time of the graft titration polymerization reaction is 2h to 2.5h, and the heat preservation time is 1h to 1.5 h.

In some embodiments of examples 3 or 4, an antioxidant and/or a preservative are further added in step S101 or S201 to specifically overcome the defects of insufficient weather resistance and easy putrefaction of the natural rubber emulsion.

In some embodiments of examples 3 or 4, step S105 or S205 further comprises adding a residual monomer treatment agent and/or neutralizing agent;

because of the high viscosity of the rubber emulsion itself, the polymerization reaction for graft modification with the monomer has a problem of polymerization imbalance, and therefore, the monomer is usually added to the rubber emulsion by slow titration, and the titration time is usually 4h to 6 h. In order to solve or partially solve the problems of uneven monomer graft polymerization and overlong titration time, the preparation method of the pressure-sensitive adhesive comprises the step of forming graft polymerization seed emulsion by prepolymerization (steps 3 and 4 in example 2 or 3), a part of mixed monomer emulsion is added into a backing material, prepolymerization is carried out in two steps, pressure-sensitive monomers, crosslinking monomers and functional monomers can be uniformly dispersed in the backing material due to less adding amount and can generate polymerization reaction with molecular chains of natural rubber to form uniformly distributed graft polymerization seeds, the pressure-sensitive monomers, the crosslinking monomers and the functional monomers can further generate polymerization reaction around the graft polymerization seeds in the next step of the residual mixed monomer emulsion graft titration polymerization reaction (step S105 or S205 in example 2 or 3) to obtain uniformly crosslinked polymer, meanwhile, the titration polymerization time can be shortened to 1h to 3h, and the production efficiency is greatly improved.

Example 5

The embodiment provides a preparation method of a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, wherein the preparation raw materials in the embodiment 1 are adopted, and the preparation method comprises the following steps:

step 1: weighing natural rubber emulsion, an antioxidant, a cross-linking agent and a preservative, sequentially injecting the natural rubber emulsion, the antioxidant, the cross-linking agent and the preservative into a first container, mixing and stirring for 15min, then injecting a grafting monomer into the first container, mixing and stirring, heating to a first reaction temperature of 50-55 ℃, keeping the temperature and stirring to obtain a backing material;

step 2: weighing deionized water, an emulsifier, a pressure-sensitive monomer, a crosslinking monomer and a functional monomer, and sequentially injecting into a second container to mix and stir at normal temperature for 15min to obtain a mixed monomer emulsion;

and step 3: injecting 5% of mixed monomer emulsion in the total mass in the second container into the first container, mixing and stirring with the bedding materials, and continuously heating to the second reaction temperature of 73-75 ℃, keeping the temperature and stirring to obtain a graft polymerization bedding material;

and 4, step 4: adding an initiator into the first container, and heating to a third reaction temperature of 83-85 ℃ to obtain a graft polymerization seed emulsion;

and 5: at a fourth reaction temperature of 81-83 ℃, injecting the residual 95% of mixed monomer in the second container into the first container for carrying out a graft titration polymerization reaction and stirring at a heat preservation temperature, wherein the titration time is controlled to be 2-2.5 h, stirring at the heat preservation temperature for 1h after the titration is finished, titrating the residual monomer treating agent into the first container when the temperature in the first container is reduced to 73-75 ℃, the titration time is 5-6 min, and continuously keeping a cooling stirring state; when the temperature in the first container is reduced to 50-55 ℃, titrating and injecting a neutralizing agent into the first container for 5-6 min;

step 6: when the temperature in the first container is reduced to 33-35 ℃, the tackifying resin is injected into the first container and mixed and stirred, and the injection time is 10-12 min, so that the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive is obtained.

Example 6

The invention provides another preparation method of a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, wherein the preparation raw materials in the embodiment 1 are adopted, and the preparation method comprises the following steps:

step 1: weighing natural rubber emulsion, an antioxidant, a cross-linking agent and a preservative, sequentially injecting into a first container, mixing and stirring for 15min, then injecting a grafting monomer into the first container, mixing and stirring, and injecting tackifying resin into the first container, mixing and stirring;

step 2: weighing deionized water, an emulsifier, a pressure-sensitive monomer, a crosslinking monomer and a functional monomer, and sequentially injecting into a second container to mix and stir at normal temperature for 15min to obtain a mixed monomer emulsion;

and step 3: injecting 5% of mixed monomer emulsion in the total mass in the second container into the first container, mixing and stirring with the bedding materials, and continuously heating to the second reaction temperature of 73-75 ℃, keeping the temperature and stirring to obtain a graft polymerization bedding material;

and 4, step 4: adding an initiator into the first container, and heating to a third reaction temperature of 83-85 ℃ to obtain a graft polymerization seed emulsion;

and 5: at a fourth reaction temperature of 81-83 ℃, injecting the residual 95% of mixed monomer in the second container into the first container for carrying out a graft titration polymerization reaction and stirring at a heat preservation temperature, wherein the titration time is controlled to be 2-2.5 h, stirring at the heat preservation temperature for 1h after the titration is finished, titrating the residual monomer treating agent into the first container when the temperature in the first container is reduced to 73-75 ℃, the titration time is 5-6 min, and continuously keeping a cooling stirring state; when the temperature in the first container is reduced to 50-55 ℃, titrating the neutralizing agent into the first container for 5-6 min to obtain the natural rubber grafted acrylate emulsion pressure-sensitive adhesive.

Example 7

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which comprises the following preparation raw materials in parts by weight:

15 parts of natural rubber emulsion;

1.12 parts of grafting monomer methacrylic acid-2-ethylhexyl ester;

14 parts of pressure-sensitive monomer butyl acrylate;

0.15 part of cross-linking monomer acrylic acid;

0.5 part of functional monomer acrylic acid-2-hydroxyethyl ester;

53.13 parts of tackifying resin rosin;

0.3 portion of emulsifier dodecyl diphenyl ether disulfonic acid sodium (2A 1);

a cross-linking agent stannous chloride aqueous emulsion, wherein the mass of the stannous chloride is 0.15 part;

0.08 part of initiator Ammonium Persulfate (APS);

15.48 parts of water.

The graft polymerization primer is prepared by the preparation method of the embodiment 3, wherein the mixed monomer emulsion injected into the first container is 5% of the total mass of the mixed monomer emulsion in the second container to form a graft polymerization primer; after initial initiation measures are carried out sequentially, the residual mixed monomer emulsion in the first container is titrated and injected into the second container for graft titration polymerization reaction, the titration graft polymerization time is 2 hours, and the heat preservation time is 1 hour. The pressure-sensitive adhesive obtained in this example was tested for its adhesive mechanical properties, initial Tack > No. 20 Ball Tack, Tack >1480gf/25mm, and permanent Tack >36h/1 kg.

Example 8

This example provides a natural rubber graft acrylate emulsion pressure sensitive adhesive, which is prepared from the same raw materials and by the same method as in example 7, except that the natural rubber emulsion is increased by 17 parts, the tackifying resin is decreased by 51.13 parts, and other raw material components are unchanged, the pressure sensitive adhesive obtained in this example has an initial adhesion of >20 Ball Tack, an adhesion of >1360gf/25mm, and a permanent adhesion of >30h/1 kg.

Example 9

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared by the same raw materials and preparation method as those in embodiment 6, and is characterized in that the natural rubber emulsion is increased by 19 parts, the tackifying resin is decreased by 49.13 parts, other raw material components are unchanged, the same method is adopted for detecting the adhesive mechanical property, and the pressure-sensitive adhesive obtained in the embodiment has the initial adhesion of No. 22Ball Tack, the adhesive force of No. 1230gf/25mm and the permanent adhesion of No. 24h/1 kg.

Example 10

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in embodiment 7, and is characterized in that the natural rubber emulsion is increased by 21.1 parts, the tackifying resin is decreased by 47.03 parts, other raw material components are unchanged, the same method is adopted for detecting the adhesive mechanical property, and the pressure-sensitive adhesive obtained in the embodiment has initial adhesion of more than 24-size Ball Tack, adhesion of more than 1150gf/25mm, and permanent adhesion of more than 24h/1 kg.

It can be seen from examples 7 to 10 that pressure-sensitive adhesives with different initial adhesion and adhesive force can be obtained by interactively adjusting the ratio of the natural rubber emulsion to the tackifying resin emulsion in the raw materials for preparation; when the proportion of the natural rubber emulsion is increased gradually, the initial adhesion is increased gradually, and the adhesive force and the permanent adhesion are reduced; when the dosage of the tackifying resin emulsion is increased, the initial adhesion is reduced, and the adhesive force and the permanent adhesion are increased.

Example 11

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from the same raw materials as in embodiment 10, and is characterized in that the preparation method described in embodiment 4 is adopted, wherein the mixed monomer emulsion injected into the first container is 5% of the total mass of the mixed monomer emulsion in the second container, the graft polymerization time is titrated for 2h, and the heat preservation time is 1 h. The pressure-sensitive adhesive obtained in this example had an initial Tack of >24 Ball Tack, an adhesive force of >1100gf/25mm, and a permanent Tack of >24h/1 kg.

Example 12

This example provides a natural rubber grafted acrylate emulsion type pressure sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in example 11, except that the natural rubber emulsion is decreased to 19 parts, the pressure sensitive monomer is increased to 16.1 parts, and other raw material components are unchanged, and the pressure sensitive adhesive obtained in this example has an initial adhesion of No. 22Ball Tack, an adhesion of No. 1270gf/25mm, and a permanent adhesion of No. 30h/1 kg.

Example 13

This example provides a natural rubber grafted acrylate emulsion type pressure sensitive adhesive, which is prepared from the same raw materials and by the same method as in example 11, except that the natural rubber emulsion is decreased to 17 parts, the pressure sensitive monomer is increased to 18.1 parts, and other raw material components are unchanged, and the pressure sensitive adhesive obtained in this example has initial adhesion greater than No. 20 Ball Tack, adhesion greater than 1350gf/25mm, and permanent adhesion greater than 36h/1 kg.

Example 14

This example provides a natural rubber grafted acrylate emulsion type pressure sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in example 11, except that the natural rubber emulsion is decreased to 15 parts, the pressure sensitive monomer is increased to 20.1 parts, and other raw material components are unchanged, and the pressure sensitive adhesive obtained in this example has initial adhesion of No. 20 Ball Tack, adhesion of No. 1460gf/25mm, and permanent adhesion of No. 36h/1 kg.

As can be seen from examples 11 to 14, the ratio of the natural rubber emulsion to the pressure-sensitive monomer was adjusted interactively to give different tack and tack; when the proportion of the natural rubber latex is decreased gradually, the initial adhesive force is decreased, and the adhesive force and the permanent adhesive force are increased gradually; when the proportion of the pressure-sensitive monomer is increased, the adhesive force and the permanent adhesion force are increased, and the initial adhesion force is reduced.

Example 15

In the comparative example provided in this example, the preparation raw materials included:

10 parts of natural rubber emulsion;

1.12 parts of grafting monomer methacrylic acid-2-ethylhexyl ester;

24 parts of pressure-sensitive monomer butyl acrylate;

0.2 part of cross-linking monomer acrylic acid;

0.7 part of functional monomer acrylic acid-2-hydroxyethyl ester;

47.03 parts of tackifying resin rosin glycerin ester emulsion;

the other components and the preparation method are the same as those of the example 6, and the pressure-sensitive adhesive obtained by the comparative example has the following adhesion mechanical property detection: initial adhesion is less than Ball Tack No. 20, adhesion is less than 980gf/25mm, permanent adhesion is less than 12h/1kg, and viscosity is 1850-1980 cps.

Example 16

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in embodiment 10, and is characterized in that 13 parts of natural rubber emulsion, 21 parts of pressure-sensitive monomer and the same other raw material components are adopted, the pressure-sensitive adhesive obtained in the embodiment has initial adhesion of more than 20 Ball Tack, adhesive force of more than 1100gf/25mm, permanent adhesion of more than 48h/1kg and viscosity of 1850-1980 cps.

Example 17

This example provides a natural rubber grafted acrylate emulsion type pressure sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in example 10, except that 15 parts of natural rubber emulsion, 19 parts of pressure sensitive monomer and the same other raw material components are used, and the pressure sensitive adhesive obtained in this example has initial adhesion greater than number 22Ball Tack, adhesion greater than 1190gf/25mm and permanent adhesion greater than 36h/1 kg.

Example 18

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from 17 parts of natural rubber emulsion, 17 parts of pressure-sensitive monomer and the same as the embodiment 10, and is characterized in that other raw material components are unchanged, the initial adhesion of the pressure-sensitive adhesive obtained in the embodiment is more than 22Ball Tack, the adhesion is more than 1280gf/25mm, the permanent adhesion is more than 24h/1kg, and the viscosity is 1850-1980 cps.

Example 19

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in embodiment 10, and is characterized in that 19 parts of natural rubber emulsion, 15 parts of pressure-sensitive monomer and the same other raw material components are adopted, and the pressure-sensitive adhesive obtained in the embodiment has initial adhesion of more than 22 balls, Ball Tack, adhesive force of more than 1370gf/25mm and permanent adhesion of more than 24h/1 kg.

Example 20

The embodiment provides a natural rubber grafted acrylate emulsion type pressure-sensitive adhesive, which is prepared from the same raw materials and by the same preparation method as in embodiment 10, and is characterized in that 21 parts of natural rubber emulsion, 13 parts of pressure-sensitive monomer and the same other raw material components are adopted, the pressure-sensitive adhesive obtained in the embodiment has initial adhesion of more than 24 Ball Tack, adhesive force of more than 1480gf/25mm, permanent adhesion of more than 24h/1kg and viscosity of 1850-1980 cps.

Example 21

The embodiment provides a pressure-sensitive adhesive product, which comprises a medium layer and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer contains the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive.

In some embodiments, the thickness of the pressure sensitive adhesive layer is between 10 μm and 50 μm, preferably, 25 μm and 50 μm.

Selecting a medium layer: selecting the material of the dielectric layer according to the requirement of the final product, wherein the material comprises one of paper, plastic film, textile, composite material, metal foil and the like for type selection confirmation and application; wherein, the paper medium comprises cotton paper, kraft paper, Japanese paper, crepe paper, beauty paper, trademark paper, photo paper, wallpaper and diversified specialty paper; the plastic film comprises a PP polypropylene film, a PE polyethylene film, a PVC polyvinyl chloride film, a PET polyester film, cellophane, a PLA degradable film, a PBAT-PLA degradable film, a PBS degradable film and a PPC degradable film; the textile fabric comprises cotton cloth, chemical fiber cloth, non-woven fabric, acetate fiber cloth and glass fiber cloth; the composite material comprises a paper-plastic composite material, a textile fabric composite material, a metal foil composite material and an aluminum-plated film composite material;

example 22

This embodiment provides a method for preparing a pressure-sensitive adhesive product, comprising the steps of:

(1) coating the pressure-sensitive adhesive in a rated thickness: on the surface of the dielectric layer, the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive is used for quantitative coating with the dry adhesive thickness of 25-30 mu m to form a wet pressure-sensitive single-sided pressure-sensitive adhesive coating;

(2) drying by a heat source: synchronously and unidirectionally coating and drying the wet pressure-sensitive single-sided pressure-sensitive adhesive coating material at 100 ℃ for 2min to form a dry pressure-sensitive single-sided pressure-sensitive adhesive coating material;

(3) winding a semi-finished product: in the process of coating and drying the pressure-sensitive single-sided pressure-sensitive adhesive coating material in the dry state, synchronously and synchronously rolling in the same direction at the rolling speed of 100 ℃ and 2min as a reference to form a semi-finished product of the pressure-sensitive single-sided adhesive tape;

(4) rewinding and cutting or splitting: rewinding, cutting or splitting the pressure-sensitive single-sided adhesive tape semi-finished product with rated width and rated length to prepare the single-sided pressure-sensitive adhesive tape product of the natural rubber grafted acrylate emulsion pressure-sensitive adhesive.

Example 23

This example provides another method for preparing a pressure sensitive adhesive product, comprising the steps of:

(1) coating the pressure-sensitive adhesive in a rated thickness: on the surface of the medium after the medium is selected, the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive is used for quantitatively coating the dry adhesive with the thickness of 45-50 mu m to form a wet pressure-sensitive single-sided pressure-sensitive adhesive coating;

(2) drying by a heat source: synchronously and unidirectionally coating and drying the wet pressure-sensitive single-sided pressure-sensitive adhesive coating material at 105 ℃ for 4min to form a dry pressure-sensitive single-sided pressure-sensitive adhesive coating material;

(3) rolling a single-side coating semi-finished product: in the process of coating and drying the pressure-sensitive single-sided pressure-sensitive adhesive coating material in the dry state, synchronously and synchronously rolling in the same direction at the rolling speed of 105 ℃ for 4min as a reference to form a semi-finished product of the pressure-sensitive single-sided coating;

(4) secondary coating of pressure-sensitive adhesive: on the back of the semi-finished product of the pressure-sensitive single-side coating, the natural rubber grafted acrylate emulsion type pressure-sensitive adhesive provided by the invention is used for coating the dry adhesive with the thickness of 45-50 mu m in a rated manner again to form a coating material with pressure-sensitive adhesive coated on both sides;

(5) secondary heat source drying: synchronously and unidirectionally coating and drying the coating material with pressure-sensitive adhesive coated on both sides at 105 ℃ for 4min to form a dry pressure-sensitive double-sided pressure-sensitive adhesive coating material;

(6) rolling a semi-finished product with pressure-sensitive adhesive coated on both sides: in the process of coating and drying the pressure-sensitive single-sided pressure-sensitive adhesive coating in the dry state, synchronously and synchronously rolling in the same direction at the rolling speed of 105 ℃ and 4min as a reference to form a semi-finished product of the pressure-sensitive double-sided adhesive tape;

(7) rewinding and cutting or splitting: rewinding, cutting or slitting the semi-finished product of the pressure-sensitive double-sided adhesive tape with rated width and rated length to prepare the double-sided pressure-sensitive adhesive tape product of the natural rubber grafted acrylate emulsion pressure-sensitive adhesive.

Example 24

This example provides an illustration of the application of the pressure sensitive adhesive product of the present invention:

the pressure-sensitive adhesive tape disclosed by the invention has the advantages that the initial adhesion is tested to be greater than 22Ball Tack, the adhesive force is greater than 1100gf/25mm, the permanent adhesion is greater than 48h/1kg, the pressure-sensitive adhesive tape is used as a cold chain food packaging tape for adhering and fixing to adapt to cold-resistant refrigeration, freezing and cold chain food packaging at the temperature of-35 ℃, and the adhesive tape has the advantages of no reduction of the viscosity, no deformation of the appearance, no color change, good air bubble and no looseness in a freezing environment of 120 h.

The pressure-sensitive adhesive tape can be used as a PVC electrical insulating tape and is suitable for insulating and bundling indoor and outdoor wires and cables in alpine regions; the adhesive tape is used for crepe paper adhesive tapes, and is painted and shielded for building decoration due to the characteristics of cold resistance and quick adhesion.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.