Production process of flame-retardant insulating hot-melt pressure-sensitive adhesive

Abstract

The invention provides a production process of a flame-retardant insulating hot-melt pressure-sensitive adhesive. The flame-retardant insulating hot-melt pressure-sensitive adhesive comprises the following raw materials in parts by weight: 50-200 parts of matrix resin, 50-100 parts of tackifying resin, 1-10 parts of a plasticizer, 0.1-5 parts of a cross-linking agent, 0.6-6 parts of an initiator, 10-15 parts of a flame retardant and 0.6-6 parts of an emulsifier, the flame retardant is adopted, the flame retardant effect of the pressure-sensitive adhesive is improved, diethyl methylphosphate is used for flame retardant modification, the prepared hot-melt pressure-sensitive adhesive has excellent flame retardant performance, azodiisobutyronitrile is used for catalytic initiation, hydroxylation of an addition product is completed in an acid environment, and then high-pressure and high-temperature reaction is used, so that the flame retardant property of the hot-melt pressure-sensitive adhesive is improved, and the flame-retardant performance of the hot-melt pressure-sensitive adhesive is improved. And a grafting reaction is carried out, so that the continuation of a combustion reaction is prevented.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of pressure-sensitive adhesives, and particularly relates to a production process of a flame-retardant and insulating hot-melt pressure-sensitive adhesive. Background Art

[0002] Pressure-sensitive adhesive is short for pressure-sensitive adhesive. There are many types of pressure-sensitive adhesives. According to the main materials, they are mainly divided into acrylate pressure-sensitive adhesives, silicone pressure-sensitive adhesives, polyurethane pressure-sensitive adhesives, thermoplastic elastomer pressure-sensitive adhesives and other pressure-sensitive adhesives, etc. It is a type of adhesive that is sensitive to pressure. Pressure-sensitive adhesives can be divided into two categories according to the main resin components: rubber type and resin type. The rubber type can be further divided into natural rubber and synthetic rubber categories; the resin type mainly includes acrylic, silicone and polyurethane types. Polyurethane pressure-sensitive adhesives are non-toxic, do not pollute the environment, and save energy. Pressure-sensitive adhesives have been widely used in technical fields such as packaging, automobiles, electronics and electrical engineering. They have the fastest growth rate in daily life and commercial application industries, such as automobiles, electronics, military, medical and other fields. There are also many product types, such as self-adhesive tapes, double-sided tapes, labels, protective films, and are used in the field of optical fiber bonding.

[0003] For specific bonding methods, generally two methods are adopted: self-adhesive layer and additional adhesive layer. In the additional adhesive layer method, usually a special hot-melt glue gun is used to heat the glue during construction, and the hot-melt glue is extruded between the wall and the optical cable for bonding. Although the production of the optical cable is convenient, the optical cable as a whole needs to have high heat resistance, and the construction professionalism and difficulty are relatively high. In the self-adhesive layer method, during construction, the invisible optical cable is directly bonded to the wall or the joint part by using a heated self-adhesive coating glue. The advantage is that the construction is relatively convenient. However, due to operations such as heating, there are still defects such as reduced transparency and appearance after bonding. If the sealing of the joint part is not good and the waterproof property is poor, there will be a very high risk, which may cause equipment short-circuit damage or fire.

[0004] In summary, the present invention provides a production process of a flame-retardant and insulating hot-melt pressure-sensitive adhesive to solve the above problems. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a production process of a flame-retardant and insulating hot-melt pressure-sensitive adhesive to solve the problems such as the defects of reduced transparency and appearance after bonding due to operations such as heating in the prior art.

[0006] A production process of a flame-retardant and insulating hot-melt pressure-sensitive adhesive includes the following raw materials in parts by weight: 50-200 parts of main resin, 50-100 parts of tackifying resin, 1-10 parts of plasticizer, 0.1-5 parts of cross-linking agent, 0.6-6 parts of initiator, 10-15 parts of flame retardant, and 0.6-6 parts of emulsifier;

[0007] The main resin is a mixture of Resin One and Resin Two. Resin One includes one or more of methyl acrylate, methyl methacrylate, butyl methacrylate, and vinyl acetate. Resin Two is one or more of acrylic acid, acrylamide, methacrylic acid, and hydroxyethyl acrylate. The weight ratio of Resin One to Resin Two is (1 - 30)∶100.

[0008] The tackifying resin includes one or more mixtures of C5 resin, rosin resin, pentaerythritol ester of rosin, glycerol ester of rosin, terpene resin, and phenolic resin;

[0009] The following steps are further included:

[0010] Step One: Add the main resin, tackifying resin, plasticizer, and crosslinking agent into a reaction vessel, and stir at a speed of 400 - 800 revolutions per minute for 2 hours;

[0011] Step Two: Add an emulsifier to the slurry obtained in Step One, and stir at a speed of 300 - 450 revolutions per minute for 0.5 - 1 hour to obtain an emulsified slurry;

[0012] Step Three: Add an initiator into the emulsified slurry and stir until it is dissolved;

[0013] Step Four: Add a flame retardant, stir at a speed of 150 - 300 revolutions per minute for 1 - 2 hours, and after vacuum defoaming for 0.5 - 1 hour, the hot melt pressure - sensitive adhesive is obtained.

[0014] Furthermore, the flame retardant is prepared through the following steps:

[0015] Step One: Under nitrogen protection, add diethyl methylphosphonate into a reaction vessel, and stir to obtain Mixture A;

[0016] Step Two: Mix KH - 570, hydroxyethyl acrylate, tetraisopropyl titanate, and DMF, and stir and react at a speed of 100 - 300 revolutions per minute for 12 - 18 hours to obtain Mixture B;

[0017] Step Three: Under nitrogen protection, stir Mixture A and Mixture B, heat up to 120 °C and react for 48 hours, cool down, perform vacuum distillation, washing, column chromatography purification, and then vacuum distillation to obtain the flame retardant.

[0018] Furthermore, in Step One of the flame retardant preparation, the oil bath is heated to 80 - 90 °C, 2,2 - azobisisobutyronitrile is mixed with vinyl acetate, and it is slowly dropped into the reaction vessel, and stirred and reacted at a speed of 100 - 30 revolutions per minute for 6 h. The particle size of the flame retardant is less than 25 μm, and 0.1 μm ≤ D50 ≤ 15 μm.

[0019] Further, the emulsifier is a mixture of ammonium lauryl sulfate and polyethylene glycol octyl phenyl ether. By weight ratio, the mass ratio of ammonium lauryl sulfate to polyethylene glycol octyl phenyl ether is (1.5 - 2):(0.5 - 1), and the antioxidant is phosphite.

[0020] Further, the plasticizer is one or a combination of more of naphthenic oil, white oil, DOP, and chlorinated paraffin.

[0021] Further, the crosslinking agent is trimethylolpropane triacrylate.

[0022] Further, the initiator is one or more of azobisisobutyronitrile, dimethyl azobisisobutyrate, and benzoyl peroxide. The initiator is preferably benzoyl peroxide.

[0023] Further, in the third step, the initiator is added dropwise in two times. After the first addition, it is stirred and dissolved. After the second addition, the water bath is heated to 75 - 85°C, and it is stirred and reacted at a speed of 100 - 150 revolutions per minute for 3 - 4 hours.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. By using a flame retardant, the present invention increases the flame retardant effect of the pressure - sensitive adhesive. It uses diethyl methylphosphonate for flame retardant modification, and the obtained hot - melt pressure - sensitive adhesive has excellent flame retardant performance. It is catalytically initiated by azobisisobutyronitrile, and the hydroxylation of the addition product is completed in an acidic environment. Then, through high - pressure and high - temperature reaction, grafting reaction occurs, thereby preventing the continuation of the combustion reaction.

[0026] 2. By using additives such as tackifying resins and softeners, the raw materials of the present invention have low toxicity, and less pollutants are generated during the preparation process. It has good high - temperature resistance. By modifying the heat - resistant filler, the high - temperature resistance and insulation performance of the pressure - sensitive adhesive are improved. The pressure - sensitive adhesive prepared by the present invention has excellent high - temperature resistance and insulation performance and has broad application prospects.

[0027] 3. The flame - retardant and insulating hot - melt pressure - sensitive adhesive prepared by the present invention has the advantages of high initial adhesion, good flame retardancy, and high coating performance and service performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the flow chart of the present invention;

[0029] Figure 2 is the flow chart of the preparation of the flame retardant of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The following further describes in detail the embodiments of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0031] As Figure 1 - Figure 2 shown, the present invention provides a production process of a flame-retardant insulating hot-melt pressure-sensitive adhesive, including the following raw materials in parts by weight: 50-200 parts of a main resin, 50-100 parts of a tackifying resin, 1-10 parts of a plasticizer, 0.1-5 parts of a cross-linking agent, 0.6-6 parts of an initiator, 10-15 parts of a flame retardant, and 0.6-6 parts of an emulsifier;

[0032] The main resin is a mixture of resin one and resin two. Resin one includes one or more of methyl acrylate, methyl methacrylate, butyl methacrylate, and vinyl acetate. Resin two is one or more of acrylic acid, acrylamide, methacrylic acid, and hydroxyethyl acrylate. The weight ratio of resin one to resin two is (1-30):100.

[0033] The tackifying resin includes one or more mixtures of C5 resin, rosin resin, pentaerythritol ester of rosin, glycerol ester of rosin, terpene resin, and phenolic resin;

[0034] It also includes the following steps:

[0035] Step one: Add the main resin, tackifying resin, plasticizer, and cross-linking agent to a reaction vessel, and stir at a speed of 400-800 revolutions per minute for 2 hours;

[0036] Step two: Add the emulsifier to the slurry in step one, and stir at a speed of 300-450 revolutions per minute for 0.5-1 hour to obtain an emulsified slurry;

[0037] Step three: Add the initiator to the emulsified slurry and stir until dissolved;

[0038] Step four: Then add the flame retardant, stir at a speed of 150-300 revolutions per minute for 1-2 hours, and obtain the hot-melt pressure-sensitive adhesive after vacuum defoaming for 0.5-1 hour.

[0039] As an embodiment of the present invention, the flame retardant is prepared through the following steps:

[0040] Step one: Under nitrogen protection, add diethyl methylphosphonate to a reaction vessel and stir to obtain mixture A;

[0041] Step two: Mix KH-570, hydroxyethyl acrylate, tetraisopropyl titanate, and DMF, and stir and react at a speed of 100-300 revolutions per minute for 12-18 hours to obtain mixture B;

[0042] Step 3: Under the protection of nitrogen, stir the mixture A and the mixture B, heat up to 120 °C and react for 48 hours, cool down, distill under reduced pressure, wash, purify by column chromatography, and distill under reduced pressure to obtain the flame retardant.

[0043] As an embodiment of the present invention, in the first step of preparing the flame retardant, heat the oil bath to 80 - 90 °C, mix 2,2 - azobisisobutyronitrile with vinyl acetate, slowly drop it into the reaction vessel, stir and react at a speed of 100 - 30 revolutions per minute for 6 h. The particle size of the flame retardant is less than 25 μm, and 0.1 μm ≤ D50 ≤ 15 μm.

[0044] As an embodiment of the present invention, the emulsifier is a mixture of ammonium dodecyl sulfate and polyethylene glycol octyl phenyl ether. By weight ratio, the mass ratio of ammonium dodecyl sulfate to polyethylene glycol octyl phenyl ether is (1.5 - 2):(0.5 - 1), and the antioxidant is phosphite.

[0045] As an embodiment of the present invention, the plasticizer is a combination of one or more of naphthenic oil, white oil, DOP, and chlorinated paraffin.

[0046] As an embodiment of the present invention, the cross - linker is trimethylolpropane triacrylate.

[0047] As an embodiment of the present invention, the initiator is one or more of azobisisobutyronitrile, dimethyl azobisisobutyrate, and benzoyl peroxide. The initiator is preferably benzoyl peroxide.

[0048] As an embodiment of the present invention, in Step 3, the initiator is added dropwise in two times. After the first addition, stir to dissolve. After the second addition, heat the water bath to 75 - 85 °C and stir and react at a speed of 100 - 150 revolutions per minute for 3 - 4 hours.

[0049] By using the flame retardant, the present invention increases the flame - retardant effect of the pressure - sensitive adhesive, uses diethyl methylphosphonate for flame - retardant modification. The obtained hot - melt pressure - sensitive adhesive has excellent flame - retardant performance. It is catalytically initiated by azobisisobutyronitrile and the hydroxylation of the addition product is completed in an acidic environment. Then, through high - pressure and high - temperature reaction, grafting reaction occurs, thereby preventing the continuation of the combustion reaction. By using additives such as tackifying resin and softening agent, the raw materials have low toxicity and less pollutants are generated during the preparation process. It has good high - temperature resistance. By modifying the heat - resistant filler, the high - temperature resistance and insulation performance of the pressure - sensitive adhesive are improved. The pressure - sensitive adhesive prepared by the present invention has excellent high - temperature resistance and insulation performance and has broad application prospects. The prepared flame - retardant and insulating hot - melt pressure - sensitive adhesive has the advantages of high initial adhesion performance, good flame - retardancy, and high coating performance and service performance.

[0050] By adopting specific crosslinking agents and tackifying resins and adjusting the dosages of the crosslinking agents and the tackifying resins, the pressure-sensitive adhesive also has excellent adhesion performance, and its mechanical properties are controllable; the volatile components in the pressure-sensitive adhesive of the present invention are close to zero, and the environmental pollution is small; the preparation method is simple to operate, low in energy consumption and low in cost.

[0051] Compared with the products in the same period of the market, the product of the present invention has a moderate viscosity, better bonding performance and flame retardant performance, and is applicable to single-sided or double-sided pressure-sensitive adhesive tapes, cables and confined spaces made of various materials with flame retardant and environmental protection requirements (low VOC), so as to quickly, stably and reliably bond the optical cable to the wall surface without continuously and repeatedly applying an adhesive layer or heating the adhesive layer on the optical cable. The operation is simple and convenient, the application scenarios are diverse, and the laying efficiency of the optical cable is significantly improved. Moreover, the production process of the hot melt pressure-sensitive adhesive is simple, the product quality is stable, and it has the advantage of large-scale continuous production.

[0052] The embodiments of the present invention are given for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A production process for a flame retardant insulating hot melt pressure sensitive adhesive, characterized in that: The invention comprises the following raw materials in parts by weight: 50 to 200 parts of main resin, 50 to 100 parts of tackifying resin, 1 to 10 parts of plasticizer, 0.1 to 5 parts of cross-linking agent, 0.6 to 6 parts of initiator, 10 to 15 parts of flame retardant and 0.6 to 6 parts of emulsifier; The main resin is a mixture of resin one and resin two, wherein resin one includes one or more of methyl acrylate, methyl methacrylate, butyl methacrylate, and vinyl acetate, and resin two is one or more of acrylic acid, acrylamide, methacrylic acid, and hydroxyethyl acrylate, and the weight ratio of resin one to resin two is (1-30):

100. The tackifying resin includes one or more mixtures of C5 resin, rosin resin, rosin pentaerythritol ester, rosin glycerol ester, terpene resin, and phenolic resin; The following steps are also included: Step 1: Add the main resin, tackifying resin, plasticizer and cross-linking agent into the reaction container, and stir at a speed of 400 to 800 rpm for 2 hours; Step 2: adding an emulsifier to the slurry of step 1, stirring at a speed of 300 to 450 rpm for 0.5 to 1 hour to obtain an emulsified slurry; Step 3: Add initiator to the emulsified slurry and stir until dissolved; Step 4: adding a flame retardant, stirring at a speed of 150 to 300 rpm for 1 to 2 hours, and performing vacuum degassing for 0.5 to 1 hour to obtain the hot melt pressure-sensitive adhesive.

2. The production process of the flame retardant insulating hot melt pressure sensitive adhesive according to claim 1, characterized in that: The flame retardant is prepared by the following steps: Step 1: under nitrogen protection, add diethyl methyl phosphate into a reaction container and stir to obtain a mixture A; Step 2: Mix KH-570, hydroxyethyl acrylate, tetraisopropyl titanate and DMF, and stir at a speed of 100 to 300 rpm for 12 to 18 hours to obtain a mixture B; Step 3: Under the protection of nitrogen, the mixture A and the mixture B are stirred, the temperature is raised to 120° C. to react for 48 hours, cooled, distilled under reduced pressure, washed, purified by column chromatography, and distilled under reduced pressure to obtain a flame retardant.

3. The production process of the flame retardant insulating hot melt pressure sensitive adhesive as claimed in claim 2, characterized in that: In the flame retardant preparation step 1, the oil bath is heated to 80-90° C., 2,2-azobisisobutyronitrile and vinyl acetate are mixed, slowly added dropwise into a reaction container, and stirred at a speed of 100-30 rpm for 6 hours. The particle size of the flame retardant is less than 25 μm, and 0.1 μm≤D50≤15 μm.

4. The production process of the flame retardant insulating hot melt pressure sensitive adhesive as claimed in claim 1, characterized in that: The emulsifier is a mixture of ammonium dodecyl sulfate and polyethylene glycol octyl phenyl ether. The mass ratio of ammonium dodecyl sulfate to polyethylene glycol octyl phenyl ether is (1.5-2):(0.5-1) by weight. The antioxidant is phosphite.

5. The production process of the flame retardant insulating hot melt pressure sensitive adhesive as claimed in claim 1, characterized in that: The plasticizer is a combination of one or more of naphthenic oil, white oil, DOP and chlorinated paraffin.

6. The production process of the flame retardant insulating hot melt pressure sensitive adhesive according to claim 1, characterized in that: The crosslinking agent is trimethylolpropane triacrylate.

7. The production process of the flame retardant insulating hot melt pressure sensitive adhesive as claimed in claim 1, characterized in that: The initiator is one or more of azobisisobutyronitrile, dimethyl azobisisobutyrate, and benzoyl peroxide, and the initiator is preferably benzoyl peroxide.

8. The production process of the flame retardant insulating hot melt pressure sensitive adhesive as claimed in claim 1, characterized in that: In the step three, the initiator is added dropwise in two portions. After the first addition, it is stirred to dissolve. After the second addition, the water bath is heated to 75-85° C. and stirred at 100-150 rpm for 3-4 hours.

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