Polyester hot-melt adhesive and insulating adhesive film prepared from polyester hot-melt adhesive

Abstract

An adhesive layer is obtained by drying an adhesive coating solution, and the coating solution comprises the following components in parts by weight: 70-90 parts of polyester resin, 10-30 parts of prepolymerized resin, 5-15 parts of other resin, 40-60 parts of flame-retardant filler, 1-2 parts of an anti-hydrolysis agent and 10-20 parts of a solvent. The polyester resin is linear saturated polyester, and has the characteristics that Tg is 10-20 DEG C, the hydroxyl value is 1-5 mgKOH / g, the acid value is less than 3 mgKOH / g, the molecular weight Mn is 15000-30000 g / mol, and 70-90 parts of polyester resin is added, the insulating adhesive film base material adopts one of PET (Polyethylene Terephthalate), PI (Polyimide) and PEN (Polyethylene Nitride) and has a single-sided structure and a double-sided structure, a single-sided film is used for adhesive insulation of cylindrical battery series parts, and a double-sided insulating adhesive film is used for adhesive fixation of signal acquisition flat cables; an adhesive film using the polyester hot melt adhesive is high in processing efficiency and strong in adhesive property, can be processed by using an automatic production line, and can meet the requirements of flame retardance, temperature resistance, high-temperature and high-humidity resistance and high-low temperature impact resistance at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesive tapes, and in particular relates to a polyester hot-melt adhesive and an insulating adhesive film made of the polyester hot-melt adhesive. Background Art

[0002] At present, the cylindrical batteries for new energy vehicles have a high degree of standardization, mature manufacturing, high battery consistency, good overall stability of the battery pack after PACK grouping, fast charge and discharge, high charging efficiency, and large output power; but because cylindrical batteries require a large number of monomer combinations, this increases the complexity and difficulty of the battery control system.

[0003] There are currently two types of insulating tapes used for the electrode series connection and current signal acquisition integrated board of the cylindrical battery control system. One uses ordinary pressure-sensitive tape, which only has an insulating function. The pressure-sensitive tape is not flame-retardant, has weak bonding strength, and the peeling force is only 1-2N / 25mm. It is also poor in weather resistance and temperature resistance. It is easy to fall off during the transportation of the integrated board and the use of the vehicle, resulting in insulation failure, battery short circuit and fire. The other uses ordinary hot-melt flame-retardant tape, which has poor heat resistance, high temperature and humidity resistance, and high and low temperature impact resistance. It is easy to fall off in low temperature environments, and cannot guarantee the 10-15 year service life of new energy vehicles.

[0004] In order to improve the deficiencies in the prior art, the present invention provides a polyurethane adhesive and a hot-pressed insulating film made of the adhesive. Compared with traditional hot-melt insulating adhesive films, the insulating film of the present invention can have very high bonding strength with films such as PET and PI and metals such as aluminum, copper, and steel through a short-time hot pressing or hot roller pressing process. At the same time, it has excellent high temperature resistance, high temperature and high humidity resistance, and high and low temperature impact resistance, and has strong market competitiveness. Summary of the invention

[0005] The object of the present invention is to provide a polyester hot melt adhesive and an insulating adhesive film using the hot melt adhesive. The polyester hot melt adhesive film has high processing efficiency, strong bonding performance, can be processed using an automated production line, and can simultaneously meet the requirements of flame retardancy, temperature resistance, high temperature and high humidity resistance, and high and low temperature impact resistance.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a polyester hot melt adhesive, wherein the adhesive layer is obtained by drying an adhesive coating liquid, and the coating liquid comprises the following components in parts by weight:

[0007] 70-90 parts of polyester resin, 10-30 parts of prepolymer resin, 5-15 parts of other resins, 40-60 parts of flame retardant filler, 1-2 parts of anti-hydrolysis agent, and 10-20 parts of solvent.

[0008] The technical solution further improved in the above technical solution is as follows:

[0009] 1. In the above scheme, the polyester resin is a linear saturated polyester with the following characteristics: Tg: 10-20°C, hydroxyl value: 1-5 mgKOH / g, acid value: <3 mgKOH / g, molecular weight Mn: 15000-30000 g / mol, and 70-90 parts are added. By using a linear saturated polyester with a large molecular weight, the flexibility and high-strength bonding performance of the hot melt adhesive can be ensured.

[0010] 2. In the above scheme, the self-made prepolymer resin is prepared by prepolymerizing a terminal hydroxyl polyester polyol resin and a flexible isocyanate at a molar equivalent ratio of NCO (isocyanate) to OH (hydroxyl) of 0.6 to 1, and adding a weight fraction ratio of 10 to 30 parts. Prepolymerizing the resin is beneficial to controlling the overflow amount and processing window of the hot melt adhesive, and at the same time, the insulating adhesive film can have excellent bonding properties and hydrolysis resistance.

[0011] 3. In the above scheme, the terminal hydroxyl polyester polyol resin is characterized by: Tg: 50-60°C, acid value: ≤10mgKOH / g; hydroxyl value: 40-75mgKOH / g, molecular weight Mn: 2000-4000g / mol.

[0012] 4. In the above scheme, the flexible isocyanate is characterized by using aliphatic polyisocyanates, such as monomers and polymers of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI).

[0013] 5. In the above scheme, the preparation method of the self-made prepolymer resin is as follows: add hydroxyl-terminated polyester polyol resin (Tg: 50-60°C, molecular weight Mn: 2000-4000g / mol; acid value: ≤10mgKOH / g; hydroxyl value: 40-75mgKOH / g) and dehydrated butanone solvent into a stainless steel reactor equipped with a stirrer, a cooling tube, and a thermometer, use nitrogen protection throughout the process, start stirring and raise the temperature to 70°C, stir until the resin is completely dissolved, keep the temperature constant, and add a catalyst 0.01% dibutyltin dilaurate, after stirring evenly, slowly add a certain proportion of flexible isocyanate (HDI), the addition time is controlled within 1 hour, after the curing agent is added, heat up to 80°C, maintain the temperature and continue to react for 2 to 3 hours, take a sample to test the infrared spectrum (FT-IR), observe whether the NCO at 2260cm-1 has disappeared, if it has disappeared, it means that the NCO reaction is complete; maintain a nitrogen atmosphere, cool to 40°C, add butanone to adjust the solid content of the prepolymer resin, and the prepolymer resin is completed.

[0014] 6. In the above scheme, the flame retardant is characterized by using one or a mixture of phosphorus (P) flame retardant and nitrogen (N) flame retardant to ensure that the insulating film has certain flame retardant properties.

[0015] 7. In the above scheme, other resins are a mixture of one or more of epoxy resin and its modified products, rosin resin and its modified products, terpene resin and its modified products, petroleum resin, phenolic resin, etc.; used to ensure that the insulating film has excellent bonding properties.

[0016] 8. In the above scheme, the anti-hydrolysis agent is carbodiimide monomer and its modified polymer; it is used to improve the hydrolysis resistance of the hot melt adhesive.

[0017] To achieve the above object, another technical solution adopted by the present invention is: a method for preparing a polyester hot melt adhesive, comprising the following steps:

[0018] (1) blending and stirring the polyester resin, prepolymer resin, other resins and solvent for 20 minutes;

[0019] (2) Slowly add the flame retardant filler into the glue, use a high-speed disperser to disperse it at high speed for 1 hour, then add the anti-hydrolysis agent and continue to disperse it for 10 minutes;

[0020] (3) Grinding the dispersed glue using a yarn grinder, and discharging the material after grinding to obtain a polyester hot melt adhesive.

[0021] The technical solution further improved in the above technical solution is as follows:

[0022] 1. In the above scheme, the polyester hot melt adhesive is made into a single-sided adhesive film and a double-sided adhesive film. The hot melt adhesive insulating film is used for the integration of new energy cylindrical battery current transmission and signal acquisition boards, mainly playing an insulating and flame-retardant role.

[0023] Furthermore, the preparation method of the single-sided insulating film is as follows: a 50 μm thick PET film is pre-corona treated, a polyester hot melt adhesive is coated on the corona surface of the PET film, the solvent is dried at 100°C / 5mins, and the thickness (dry) of the adhesive layer is 50 μm to make a single-sided insulating film.

[0024] Furthermore, the preparation method of the double-sided insulating film is as follows: after compounding a protective film on the prepared single-sided insulating film, a layer of polyester hot-melt adhesive with a thickness (dry) of 50 μm is continuously coated on the other side to prepare a double-sided insulating film.

[0025] 2. In the above scheme, the substrate is one of PET (polyethylene terephthalate), PI (polyimide), and PEN (polyethylene naphthalate). The preferred film thickness is 15 μm to 75 μm.

[0026] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0027] 1. The polyester hot melt adhesive of the present invention can be quickly bonded to metal materials. The insulating film substrate uses one of PET (polyethylene terephthalate), PI (polyimide), and PEN (polyethylene naphthalate). There are two types of insulating films, single-sided and double-sided. The single-sided film is used for bonding and insulation of cylindrical battery series components, and the double-sided insulating film is used for bonding and fixing of signal acquisition flat cables. The film using the polyester hot melt adhesive has high processing efficiency and strong bonding performance. It can be processed using an automated production line and can meet the flame retardancy, temperature resistance, high temperature and humidity resistance, and high and low temperature impact resistance.

[0028] 2. The insulating adhesive film of the present invention can have high bonding strength with films such as PET and PI and metals such as aluminum, copper, and steel through a short-time hot pressing or hot roller pressing laminating process, and at the same time has excellent high temperature resistance, high temperature and high humidity resistance, and high and low temperature impact resistance. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with embodiments:

[0030] Table 1 shows the raw materials for preparing prepolymer resin.

[0031] Table 1

[0032]

[0033]

[0034] Example

[0035] Example 1

[0036] Single-sided hot melt adhesive film, using PET substrate film thickness 50μm, adhesive layer thickness: 50μm;

[0037] Hot melt adhesive weight ratio: polyester resin ES-360 80 parts, prepolymer resin R1 20 parts, flame retardant filler OP93550 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0038] Example 2

[0039] Single-sided hot melt adhesive film, using PET substrate film thickness 50μm, adhesive layer thickness: 50μm;

[0040] Hot melt adhesive weight ratio: polyester resin ES-360 90 parts, prepolymer resin R2 10 parts, flame retardant filler OP93550 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1.5 parts, solvent MEK 10 parts.

[0041] Example 3

[0042] Single-sided hot melt adhesive film, using PET substrate film thickness 50μm, adhesive layer thickness: 50μm;

[0043] Hot melt adhesive weight ratio: polyester resin ES-360 80 parts, prepolymer resin R3 20 parts, flame retardant filler OP93545 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0044] Example 4

[0045] Single-sided hot melt adhesive film, using PET substrate film thickness 50μm, adhesive layer thickness: 50μm;

[0046] Hot melt adhesive weight ratio: polyester resin ES-360 75 parts, prepolymer resin R4 25 parts, flame retardant filler OP93555 parts, other resin GB120 8 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0047] Example 5

[0048] Single-sided hot melt adhesive film, using PET substrate film thickness 50μm, adhesive layer thickness: 50μm;

[0049] Hot melt adhesive weight ratio: polyester resin ES-360 80 parts, prepolymer resin R5 20 parts, flame retardant filler OP93542 parts, other resin GB120 15 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0050] Example 6

[0051] Single-sided hot melt adhesive film, using PET substrate film thickness 50um, adhesive layer thickness: 50um;

[0052] Hot melt adhesive weight ratio: polyester resin AL072 85 parts, prepolymer resin R3 15 parts, flame retardant filler OP93550 parts, other resin GB120 15 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0053] Example 7

[0054] Single-sided hot melt adhesive film, using PET substrate film thickness 50um, adhesive layer thickness: 50um;

[0055] Hot melt adhesive weight ratio: polyester resin AL072 90 parts, prepolymer resin R5 10 parts, flame retardant filler OP93540 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0056] Example 8

[0057] Double-sided hot melt adhesive film, using PET substrate film thickness 50um, first layer adhesive thickness: 50um, second layer adhesive thickness: 50um;

[0058] Hot melt adhesive weight ratio: polyester resin AL072 70 parts, prepolymer resin R5 30 parts, flame retardant filler OP93560 parts, other resin GB120 5 parts, anti-hydrolysis agent 1010 2 parts, solvent MEK 10 parts.

[0059] The above components are specifically:

[0060] ES-360, polyester resin, South Korea SK Chemical, hydroxyl value: 3mgKOH / g, acid value: <3mgKOH / g, Tg: 17℃, molecular weight Mn: 28000.

[0061] AL072, polyester resin, Hanhai New Materials, hydroxyl value: 4mgKOH.g, acid value: <3mgKOH / g, Tg: 12℃, molecular weight Mn: 26000.

[0062] VYLON 220, polyester resin, Toyobo, Japan, hydroxyl value: 50 mgKOH / g, acid value: <2 mgKOH / g, Tg: 53°C, molecular weight Mn: 3000.

[0063] GB120, rosin resin, Arakawa Chemical, acid value: 10-20 mgKOH / g, softening point: 117-126℃.

[0064] OP935, phosphite flame retardant, Clariant Chemicals;

[0065] 1010, carbodiimide, Langyi Technology;

[0066] DBTDL, dibutyltin dilaurate, Aladdin Chemical, China;

[0067] TPA100, isocyanate resin, HDI trimer, Asahi kasei, Japan;

[0068] Comparative Example

[0069] Comparative Example 1, single-sided hot melt adhesive film, using PET substrate with a film thickness of 50 μm, adhesive layer thickness: 50 μm

[0070] Hot melt adhesive weight ratio: polyester resin ES-360 80 parts, prepolymer resin R6 20 parts, flame retardant filler OP93550 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0071] Comparative Example 2, single-sided hot melt adhesive film, using PET substrate with a film thickness of 50 μm, adhesive layer thickness: 50 μm

[0072] Hot melt adhesive weight ratio: polyester resin ES-360 80 parts, prepolymer resin R7 20 parts, flame retardant filler OP93550 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0073] Comparative Example 3, single-sided hot melt adhesive film, using PET substrate with a film thickness of 50 μm, adhesive layer thickness: 50 μm

[0074] Hot melt adhesive weight ratio: polyester resin ES-360 100 parts, flame retardant filler OP935 50 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0075] Comparative Example 4, single-sided hot melt adhesive film, using PET substrate with a film thickness of 50 μm, adhesive layer thickness: 50 μm

[0076] Hot melt adhesive weight ratio: polyester resin ES-360 60 parts, prepolymer resin R4 40 parts, flame retardant filler OP93550 parts, other resin GB120 10 parts, anti-hydrolysis agent 1010 1 part, solvent MEK 10 parts.

[0077]

[0078] ◎: indicates the best overall performance; ○: indicates the performance is OK and can meet the use requirements;

[0079] △: indicates poor performance; ×: indicates extremely poor performance.

[0080] Evaluation method:

[0081] Peel strength (N / mm): Cut the film into 300mm wide and 150mm long, fix the cut film on 0.12mm thick aluminum foil, use temperature 140-160℃ / hot pressing time 1min / pressure 0.5Mpa hot pressing, cool to room temperature and test 180° peeling, speed 100mm / min.

[0082] Glue overflow (mm): Cut the film into 3 samples of 10cm*10cm size, punch holes with a punching machine, and stick the punched samples on 0.12mm thick aluminum foil. Use temperature 140-160℃ / time 1min / pressure 0.5Mpa for hot pressing. After hot pressing, test the glue overflow at the punching position.

[0083] High temperature and high humidity aging test (85°C×85%RH / 1000H): Same as sample preparation method 1 and 2, put the sample into the high temperature and high humidity environment box for 1000H, take it out and cool it to room temperature, test the peel strength, 180° peeling, 100mm / min speed.

[0084] Thermal shock aging test (-40℃~105℃ / 1000 cycles): Same as sample preparation method 1, put the sample into the thermal shock environment box for 1000H, -40℃ / 0.5H, 105℃ / 0.5H, the hot and cold switching time is within 2mins. After 1000 cycles, take out and cool to room temperature, test the peel strength, 180° peeling, 100mm / min speed.

[0085] High temperature aging test (aging at 125°C for 1000 hours): The same sample preparation method as 1 was used. The sample was placed in a high temperature oven for 1000 hours. After aging for 1000 hours, it was taken out and cooled to room temperature. The peel strength was tested by 180° peeling at a speed of 100 mm / min.

[0086] According to the above experimental results, it can be seen that the initial bonding strength of comparative examples 1 and 2 is significantly lower than that of the embodiment, and the bonding strength after hot and cold shock is also lower than the requirement for actual use; the bonding strength of comparative examples 1, 2, and 3 after aging at 85°C, 85% RH for 1000 hours and the bonding strength after aging at 125°C for 1000 hours do not meet the use requirements, and the amount of glue overflow in comparative examples 1, 3, and 4 is too high, which has seriously affected the actual use effect.

[0087] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A polyester hot melt adhesive, characterized in that: The adhesive layer is obtained by drying an adhesive coating liquid, wherein the coating liquid comprises the following components in parts by weight: 70-90 parts of polyester resin, 10-30 parts of prepolymer resin, 5-15 parts of other resins, 40-60 parts of flame retardant filler, 1-2 parts of anti-hydrolysis agent, and 10-20 parts of solvent.

2. The polyester hot melt adhesive according to claim 1, characterized in that: The polyester resin is a linear saturated polyester with the following characteristics: Tg: 10-20°C, hydroxyl value: 1-5 mgKOH / g, acid value: <3 mgKOH / g, molecular weight Mn: 15000-30000 g / mol, and 70-90 parts are added.

3. The polyester hot melt adhesive according to claim 1, characterized in that: The prepolymer resin is prepared by prepolymerizing hydroxyl-terminated polyester polyol resin and flexible isocyanate at a molar equivalent ratio of NCO (isocyanate group) to OH (hydroxyl group) of 0.6 to 1.

4. The polyester hot melt adhesive according to claim 3, characterized in that: The characteristics of the hydroxyl-terminated polyester polyol resin are: Tg: 50-60°C, acid value: ≤10mgKOH / g; Hydroxyl value: 40-75 mgKOH / g, molecular weight Mn: 2000-4000 g / mol.

5. The polyester hot melt adhesive according to claim 3, characterized in that: The flexible isocyanate is an aliphatic polyisocyanate.

6. The polyester hot melt adhesive according to claim 3, characterized in that: The preparation method of the prepolymer resin comprises the following steps: adding a hydroxyl-terminated polyester polyol resin and a dehydrated butanone solvent into a stainless steel reaction kettle with a stirrer, a cooling tube and a thermometer, using nitrogen protection throughout the process, starting stirring and heating to 60-70°C, stirring until the resin is completely dissolved, maintaining a constant temperature, adding a catalyst, stirring evenly, slowly adding a certain proportion of flexible isocyanate (HDI), and controlling the adding time to be 0.5-1h, heating to 70-80°C after the curing agent is added, maintaining the temperature and continuing the reaction for 2-3h, sampling and testing infrared spectrum (FT-IR), observing whether NCO at 2260cm-1 has disappeared, and if it has disappeared, it means that the NCO reaction is complete; maintaining a nitrogen atmosphere, cooling to 35-45°C, adding butanone to adjust the solid content of the prepolymer resin to 45%, and the preparation of the prepolymer resin is completed.

7. The polyester hot melt adhesive according to claim 1, characterized in that: The flame retardant is one or a mixture of two of a phosphorus (P) flame retardant and a nitrogen (N) flame retardant; The other resin is a mixture of one or more of epoxy resin and its modified product, rosin resin and its modified product, terpene resin and its modified product, petroleum resin, phenolic resin, etc.; The anti-hydrolysis agent is a carbodiimide monomer and a modified polymer thereof.

8. A method for preparing the polyester hot melt adhesive according to claim 1, characterized in that: The following steps are involved: (1) blending polyester resin, prepolymer resin, other resins and solvent and stirring them uniformly; (2) slowly adding the flame retardant filler into the glue, dispersing it at high speed using a high-speed disperser, and then adding an anti-hydrolysis agent to continue dispersing; (3) Grinding the dispersed glue using a yarn grinder, and discharging the material after grinding to obtain a polyester hot melt adhesive.

9. A method for preparing an insulating film made from the polyester hot melt adhesive according to claim 1, characterized in that: The polyester hot melt adhesive is made into a single-sided adhesive film or a double-sided adhesive film; The preparation method of the single-sided insulating adhesive film is as follows: corona treatment is performed on the PET film in advance, a polyester hot melt adhesive is applied to the corona surface of the PET film, and drying is performed to prepare the single-sided insulating adhesive film; The preparation method of the double-sided insulating adhesive film is as follows: after compounding a protective film on the prepared single-sided insulating adhesive film, a layer of polyester hot-melt adhesive is continuously coated on the other side to prepare the double-sided insulating adhesive film.

10. The method for preparing an insulating adhesive film according to claim 9, characterized in that: The substrate uses one of PET (polyethylene terephthalate), PI (polyimide), and PEN (polyethylene naphthalate), and has a thickness of 15 μm to 75 μm.

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