Binding material suitable for PVDF and EVOH bonding and preparation method thereof

Abstract

The invention belongs to the technical field of bonding materials, and particularly relates to a bonding material suitable for PVDF and EVOH bonding and a preparation method thereof, the bonding material is characterized by comprising the following components by weight: 20-30 parts of double modified PVDF, 20-30 parts of EAA, 30-50 parts of modified linear low density polyethylene, 1-5 parts of tackifying resin, 1-10 parts of a plasticizer, and 0.1-3 parts of an antioxidant. The adhesive material has the advantages that the bonding strength of the adhesive material can well meet the bonding requirements of EVOH and PVDF, and the adhesive material is stable in performance. Polar functional groups such as hydroxyl, ester group and the like are used as reactive monomers to graft PVDF, so that the adhesion between PVDF and other materials and the compatibility between PVDF and other polymers are effectively enhanced; under the synergistic effect of polar groups of the double-modified PVDF, the modified linear low-density polyethylene and acid anhydride and carboxyl of EAA, the bonding performance of the bonding material is more remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of bonding materials, and in particular relates to a bonding material suitable for bonding PVDF and EVOH and a preparation method thereof. Background Art

[0002] Multilayer composite pipes are favored and valued by people because of their excellent mechanical, chemical flame retardant and other properties, and are widely used in various fields. The structure of the composite pipe is divided into several functional layers, such as outer layer, inner layer, barrier layer, etc. Commonly used materials are PA6, PA11, PA12, PP, PPR, HDPE, PERT, PVDF, EVOH, etc. Polyvinylidene fluoride (PVDF) is a high-performance material with semi-crystalline characteristics. It has excellent chemical stability to solvents, acids and alkalis, excellent high temperature resistance, oxidation resistance, radiation resistance, and excellent mechanical properties and processability. It is suitable for use as the outer or inner layer material of the composite pipe. EVOH has always been the most widely used high-barrier material and is often used as a barrier layer material. It has excellent barrier properties and processing properties for gases, and exhibits very excellent performance in transparency, gloss, mechanical strength, elasticity, wear resistance, cold resistance and surface strength. The inner layer or outer layer and the barrier layer usually need adhesive materials for bonding, but PVDF is a non-polar material, lacking polar groups, and has disadvantages such as poor adhesion to the substrate and poor compatibility with other polymers, which also makes it difficult to bond PVDF and EVOH. Maleic anhydride grafted polyethylene adhesives and ethylene-ethyl acrylate (EEA) copolymer adhesives are commonly used for bonding the functional layer. During use, the composite pipe is very prone to delamination and separation, which seriously affects the quality of the product.

[0003] Therefore, developing an adhesive material specifically for bonding PVDF and EVOH is of great significance for the application of PVDF and EVOH. Summary of the invention

[0004] The purpose of the present invention is to provide an adhesive material suitable for bonding PVDF and EVOH and a preparation method thereof, so as to overcome the shortcomings of the prior art, meet the needs of bonding EVOH and PVDF materials, have stable performance and high bonding force, enhance the adhesion of PVDF to itself and other materials and the compatibility with other polymers, and improve the bonding performance of the adhesive material.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] Technical solution 1: An adhesive material suitable for bonding PVDF and EVOH, wherein the components thereof include, by weight: 20-30 parts of double-modified PVDF, 20-30 parts of EAA, 30-50 parts of modified linear low-density polyethylene, 1-5 parts of tackifying resin, 1-10 parts of plasticizer, and 0.1-3 parts of antioxidant.

[0007] The physical and chemical characteristics of the double-modified PVDF are 1%-3% and the density is 1.75g / cm 3 -1.78g / cm 3 .

[0008] The EAA is an ethylene-acrylic acid copolymer with a density of 0.94 g / cm3, a melt flow index of 8 g / min, and a methacrylic acid content of 20%.

[0009] The plasticizer is any one of di-n-octyl phthalate, butyl phthalate, dinonyl phthalate, and di-n-butyl sebacate, or a combination of any two or more thereof.

[0010] The modified linear low-density polyethylene is maleic anhydride grafted polyethylene, with a melt flow index of 2.5 g / min, a relative density of 0.94-0.96 g / cm3, and a maleic anhydride grafting rate of 0.9-1.2%.

[0011] The tackifying resin is any one of styrene resin, polytricyclodecane methacrylate resin, and rosin derivative resin, or a combination of any two or more thereof, and has a molecular weight of 7000-10000.

[0012] The antioxidant is any one of antioxidant 168, antioxidant 1010, antioxidant B215, and antioxidant B225, or a combination of any two or more thereof.

[0013] Technical solution two: A method for preparing an adhesive material suitable for bonding PVDF and EVOH, wherein each component of double-modified PVDF, EAA, modified linear low-density polyethylene, tackifying resin, plasticizer and antioxidant is added to a high-speed mixer in proportion and mixed; the evenly mixed material is added to a twin-screw extruder for extrusion, and the extruded material strips are cooled to room temperature through a circulating water tank, dried by a hair dryer, and then granulated in a pelletizer to obtain an adhesive material, which is heated to a molten state before use.

[0014] The temperature of each temperature zone of the twin-screw extruder is 130-180°C.

[0015] The double modified PVDF is prepared according to the following steps: 1) pretreatment: drying PVDF, 2-methyl-2-acrylic acid-2,3-dihydroxypropyl ester (DPMA) and 3,4-epoxycyclohexylmethyl methacrylate (ECMMA) at 50-80° C. for 12-24 hours respectively; 2) mixing: adding the dried PVDF: DPMA: EMMA in a ratio of 86-90 parts by weight: 5-7 parts: 5-7 parts by weight to a torque rheometer, and then adding an initiator, wherein the mass ratio of the initiator is 0.05-0.1 parts; 3) reaction: reacting at 190-210° C. for 5-7 minutes, the speed of the torque rheometer is 40-60 rpm, and after the reaction is completed, taking out the reaction product and cooling it, filtering, washing and drying it to obtain the double modified PVDF;

[0016] The molecular weight of the PVDF is 90,000-200,000, and the form is granules or powder;

[0017] The initiator is any one of benzoyl peroxide (BPO), lauryl peroxide (LPO), tert-butyl benzoyl peroxide and acetophenone peroxide.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) The bonding strength of the adhesive material prepared by mixing double-modified PVDF, EAA, modified linear low-density polyethylene, tackifying resin, plasticizer and antioxidant according to specified weight proportions can well meet the requirements of EVOH and PVDF bonding, and has stable performance and high bonding force.

[0020] 2) The introduction of DPMA and ECMMA allows polar functional groups such as hydroxyl and ester groups to be grafted onto PVDF as reactive monomers, effectively enhancing the adhesion of PVDF to itself and other materials as well as its compatibility with other polymers;

[0021] 3) The synergistic effect of the polar groups of the double-modified PVDF by DPMA and ECMMA and the anhydride and carboxyl groups of the modified linear low-density polyethylene and EAA significantly improves the bonding performance of the bonding material. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the specific embodiments required to be used in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the present invention. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying creative work.

[0024] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the invention claimed, but merely represents selected embodiments of the present invention.

[0025] In the following examples, the physical and chemical characteristics of the double-modified PVDF are 1%-3% and the density is 1.75 g / cm 3 -1.78g / cm 3 . EAA is an ethylene-acrylic acid copolymer. The plasticizer is any one of di-n-octyl phthalate, butyl phthalate, dinonyl phthalate, and di-n-butyl sebacate, or a combination of any two or more thereof. The modified linear low-density polyethylene is maleic anhydride grafted polyethylene, and its melt flow index is 2.5 g / min and its relative density is 0.94-0.96 g / cm3. The tackifying resin is any one of styrene resin, polytricyclodecane methacrylate resin, and rosin derivative resin, or a combination of any two or more thereof. The antioxidant is any one of antioxidant 168, antioxidant 1010, antioxidant B215, and antioxidant B225, or a combination of any two or more thereof.

[0026] The molecular weight of PVDF is 90000-200000, and the form is granules or powders; the initiator is any one of benzoyl peroxide (BPO), lauryl peroxide (LPO), tert-butyl benzoyl peroxide and acetophenone peroxide.

[0027] Example 1

[0028] In Example 1 of the present invention, the double-modified PVDF is prepared according to the following steps: 1) pretreatment: PVDF (molecular weight 15000), DPMA and EMMA are dried at 80°C for 12h respectively; 2) mixing: the dried PVDF: DPMA: EMMA is added to a torque rheometer in a mass ratio of 85.9 parts: 7 parts: 7 parts, and 0.1 parts of benzoyl peroxide (BPO) is added as an initiator; 3) reaction: the reaction is carried out at 200°C for 7min, the speed of the torque rheometer is 60rpm, after the reaction is completed, the torque rheometer is turned off, the reaction product is taken out and cooled, filtered, washed and dried to obtain the double-modified PVDF;

[0029] In Example 1 of the present invention, the preparation method of the adhesive material suitable for bonding PVDF and EVOH is as follows: 20 parts of the obtained double-modified PVDF, 30 parts of EAA, 40 parts of modified linear low-density polyethylene, 2 parts of styrene resin, 6 parts of di-n-octyl phthalate and 0.5 parts of antioxidant 168 are dried at 80°C for 12 hours, and the above components are added to a high-speed mixer and mixed evenly; added to a twin-screw extruder for extrusion, the extruded material strips are cooled to room temperature through a circulating water tank, and then dried by a hair dryer and then granulated in a pelletizer to obtain an adhesive material, which is heated to a molten state for use. The temperature of each temperature zone of the twin-screw extruder is 130-170°C, the barrel temperature of the extruder is 130-150°C, and the head temperature of the extruder is 150-170°C.

[0030] In the application of composite pipes, EVOH material is used as a barrier layer, and PVDF material is used as the inner layer of the composite pipe. When in use, an adhesive material is required to bond the two materials to ensure that the composite pipe does not delaminate or separate during use. The adhesive material is placed between the EVOH barrier layer and the PVDF inner layer, melted into a colloid at 200°C, and maintained at a pressure of 1Mpa for 10 minutes.

[0031] Example 2

[0032] In Example 2 of the present invention, the double-modified PVDF is prepared according to the following steps: 1) Pretreatment: PVDF (molecular weight 15000), 2-methyl-2-acrylic acid-2,3-dihydroxypropyl ester (DPMA) and 3,4-epoxycyclohexyl methyl methacrylate (ECMMA) are dried at 50°C for 12-24h and 24h respectively; 2) Mixing: The dried PVDF: DPMA: EMMA is added to a torque rheometer in a mass ratio of 89.9 parts: 5 parts: 5 parts, and 0.1 parts of lauryl peroxide (LPO) is added as an initiator; 3) Reaction: The reaction is carried out at 195°C for 5min, and the speed of the torque rheometer is 50rpm. After the reaction is completed, the torque rheometer is turned off, the reaction product is taken out and cooled, filtered, washed and dried to obtain the double-modified PVDF.

[0033] In Example 2 of the present invention, the preparation method of the adhesive material suitable for bonding PVDF and EVOH is as follows: 25 parts of the obtained double-modified PVDF, 25 parts of EAA, 45 parts of modified linear low-density polyethylene, 1 part of polytricyclic methacrylate resin, 10 parts of butyl phthalate and 0.1 parts of antioxidant 1010 are added to each component, and dried at 80°C for 12 hours, and the above components are added to a high-speed mixer and mixed evenly; added to a twin-screw extruder for extrusion, and the extruded material strips are cooled to room temperature through a circulating water tank, and after being blown and dried by a hair dryer, they enter a pelletizer for granulation to obtain an adhesive material, which is heated to a molten state for use. The temperature of each temperature zone of the twin-screw extruder is 140-180°C, the barrel temperature of the extruder is 140-160°C, and the head temperature of the extruder is 160-180°C.

[0034] In the application of composite pipes, EVOH material is used as a barrier layer, and PVDF material is used as the inner layer of the composite pipe. When in use, an adhesive material is required to bond the two materials to ensure that the composite pipe does not delaminate or separate during use. The adhesive material is placed between the EVOH barrier layer and the PVDF inner layer, melted into a colloid at 200°C, and maintained at a pressure of 1Mpa for 10 minutes.

[0035] Example 3

[0036] In Example 3 of the present invention, the double-modified PVDF is prepared according to the following steps: 1) pretreatment: PVDF (molecular weight 15000), 2-methyl-2-acrylic acid-2,3-dihydroxypropyl ester (DPMA) and 3,4-epoxycyclohexylmethyl methacrylate (ECMMA) are dried at 70°C for 20 hours respectively; 2) mixing: the dried PVDF: DPMA: EMMA is added to a torque rheometer in a mass ratio of 87.95 parts: 6 parts: 6 parts, and 0.05 parts of tert-butyl peroxide benzoyl is added as an initiator; 3) reaction: react at 210°C for 6 minutes, the speed of the torque rheometer is 60rpm, after the reaction is completed, the torque rheometer is turned off, the reaction product is taken out and cooled, filtered, washed and dried to obtain the double-modified PVDF.

[0037] In Example 3 of the present invention, the preparation method of the adhesive material suitable for bonding PVDF and EVOH is as follows: 30 parts of the obtained double-modified PVDF, 28 parts of EAA, 50 parts of modified linear low-density polyethylene, 5 parts of allyl diglycol carbonate, 3 parts of dinonyl phthalate and antioxidant B225 are 3 parts of each component, and they are dried at 80°C for 12 hours respectively, and the above components are added to a high-speed mixer and mixed evenly; they are added to a twin-screw extruder for extrusion, and the extruded material strips are cooled to room temperature through a circulating water tank, and after being blown and dried by a hair dryer, they enter a pelletizer for granulation to obtain an adhesive material, which is heated to a molten state for use. The temperature of each temperature zone of the twin-screw extruder is 135-160°C, the barrel temperature of the extruder is 135-145°C, and the head temperature of the extruder is 145-160°C.

[0038] In the application of composite pipes, EVOH material is used as a barrier layer, and PVDF material is used as the inner layer of the composite pipe. When in use, an adhesive material is required to bond the two materials to ensure that the composite pipe does not delaminate or separate during use. The adhesive material is placed between the EVOH barrier layer and the PVDF inner layer, melted into a colloid at 200°C, and maintained at a pressure of 1Mpa for 10 minutes.

[0039] Example 4

[0040] In Example 4 of the present invention, the double modified PVDF is prepared according to the following steps: 1) Pretreatment: PVDF (molecular weight 15000), 2-methyl-2-acrylic acid-2,3-dihydroxypropyl ester (DPMA) and 3,4-epoxycyclohexylmethyl methacrylate (ECMMA) are dried at 60°C for 18h; 2) Mixing: The dried PVDF: DPMA: EMMA is added to a torque rheometer in a mass ratio of 88.93 parts: 5.5 parts: 5.5 parts, and 0.07 parts of acetophenone peroxide is added as an initiator; 3) Reaction: The reaction is carried out at 210°C for 6min, and the speed of the torque rheometer is 60rpm. After the reaction is completed, the torque rheometer is turned off, the reaction product is taken out and cooled, filtered, washed and dried to obtain the double modified PVDF.

[0041] In Example 4 of the present invention, the preparation method of the adhesive material suitable for bonding PVDF and EVOH is as follows: 28 parts of the obtained double-modified PVDF, 30 parts of EAA, 43 parts of modified linear low-density polyethylene, 4 parts of rosin derivative resin, 1 part of di-n-butyl sebacate and 2 parts of antioxidant B215 are dried at 80°C for 12 hours, and the above components are added to a high-speed mixer and mixed evenly; added to a twin-screw extruder for extrusion, the extruded material strips are cooled to room temperature through a circulating water tank, and then dried by a hair dryer and then granulated in a pelletizer to obtain an adhesive material, which is heated to a molten state for use. The temperature of each temperature zone of the twin-screw extruder is 135-160°C, the barrel temperature of the extruder is 135-145°C, and the head temperature of the extruder is 145-160°C.

[0042] In the application of composite pipes, EVOH material is used as a barrier layer, and PVDF material is used as the inner layer of the composite pipe. When in use, an adhesive material is required to bond the two materials to ensure that the composite pipe does not delaminate or separate during use. The adhesive material is placed between the EVOH barrier layer and the PVDF inner layer, melted into a colloid at 200°C, and maintained at a pressure of 1Mpa for 10 minutes.

[0043] Comparative Example 1

[0044] Commercially available maleic anhydride grafted polyethylene adhesive was used.

[0045] Comparative Example 2

[0046] A commercially available ethylene-ethyl acrylate (EEA) copolymer adhesive was used.

[0047] The adhesive materials obtained in the above examples 1-4 were tested and compared with the comparative examples 1-2. The peel strength performance test was performed according to the standard GB / T2790. The interlayer shear performance test was performed according to the standard GB / T 1405.1. The longitudinal elongation performance test was performed according to the standard GB / T 1040. The thermal expansion phenomenon was observed by heating at 120°C for 30 minutes.

[0048] The test results of the adhesive materials obtained in the above-mentioned Examples 1-4 and Comparative Examples 1-2 are compared in Table 1.

[0049] Table 1

[0050]

[0051] In summary, the peel strength of the bonding using the bonding materials of Examples 1-5 is 170-186N / 25mm. Compared with Comparative Examples 1-2, the bonding effect is good, which can well meet the bonding needs of PVDF and EVOH, solve the problem of difficult bonding between PVDF and EVOH, and ensure that the finished composite pipe does not delaminate or separate during use.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An adhesive material suitable for bonding PVDF and EVOH, characterized in that: The components thereof include, by weight: 20-30 parts of double-modified PVDF, 20-30 parts of EAA, 30-50 parts of modified linear low-density polyethylene, 1-5 parts of tackifying resin, 1-10 parts of plasticizer, and 0.1-3 parts of antioxidant.

2. The bonding material suitable for bonding PVDF and EVOH according to claim 1, characterized in that: The physical and chemical characteristics of the double-modified PVDF are a grafting rate of 1%-3% and a density of 1.75 g / cm 3 -1.78g / cm 3 .

3. The bonding material suitable for bonding PVDF and EVOH according to claim 1, characterized in that: The EAA is an ethylene-acrylic acid copolymer with a density of 0.94 g / cm 3 , melt flow index is 8 g / min, and methacrylic acid content is 20%.

4. The bonding material suitable for bonding PVDF and EVOH according to claim 1, characterized in that: The plasticizer is any one of di-n-octyl phthalate, butyl phthalate, dinonyl phthalate, and di-n-butyl sebacate, or a combination of any two or more thereof.

5. The bonding material suitable for bonding PVDF and EVOH according to claim 1, characterized in that: The modified linear low-density polyethylene is maleic anhydride grafted polyethylene, with a melt flow index of 2.5 g / min and a relative density of 0.94-0.96 g / cm 3 , the maleic anhydride grafting rate is 0.9-1.2%.

6. The bonding material suitable for bonding PVDF and EVOH according to claim 1, characterized in that: The tackifying resin is any one of styrene resin, polytricyclodecane methacrylate resin, and rosin derivative resin, or a combination of any two or more thereof, and has a molecular weight of 7000-10000.

7. The bonding material suitable for bonding PVDF and EVOH according to claim 1, characterized in that: The antioxidant is any one of antioxidant 168, antioxidant 1010, antioxidant B215, and antioxidant B225, or a combination of any two or more thereof.

8. A method for preparing an adhesive material suitable for bonding PVDF and EVOH, characterized in that: The double-modified PVDF, EAA, modified linear low-density polyethylene, tackifying resin, plasticizer and antioxidant components are added to a high-speed mixer in proportion and mixed; the uniformly mixed materials are added to a twin-screw extruder for extrusion, and the extruded material strips are cooled to room temperature through a circulating water tank, dried by a hair dryer, and then granulated in a pelletizer to obtain an adhesive material, which is heated to a molten state before use.

9. The method for preparing a bonding material suitable for bonding PVDF and EVOH according to claim 8, characterized in that: The temperature of each temperature zone of the twin-screw extruder is 130-180°C.

10. The method for preparing an adhesive material suitable for bonding PVDF and EVOH according to claim 8, characterized in that: The double modified PVDF is prepared according to the following steps: 1) Pretreatment: drying PVDF, 2-methyl-2-acrylic acid-2,3-dihydroxypropyl ester (DPMA) and 3,4-epoxycyclohexylmethyl methacrylate (ECMMA) at 50-80° C. for 12-24 h respectively; 2) Mixing: Add the dried PVDF: DPMA: EMMA into the torque rheometer in a ratio of 86-90 parts by weight: 5-7 parts by weight: 5-7 parts by weight, and then add the initiator in a ratio of 0.05-0.1 parts by weight; 3) Reaction: react at 190-210°C for 5-7 minutes, with the speed of the torque rheometer being 40-60 rpm. After the reaction is completed, the reaction product is taken out and cooled, filtered, washed and dried to obtain the double-modified PVDF; The molecular weight of the PVDF is 90,000-200,000, and the form is granules or powder; The initiator is any one of benzoyl peroxide (BPO), lauryl peroxide (LPO), tert-butyl benzoyl peroxide and acetophenone peroxide.

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