Dimer acid type polyamide hot melt adhesive and preparation method thereof

Abstract

The invention provides a dimer acid type polyamide hot melt adhesive and a preparation method thereof. The polyamide hot melt adhesive comprises the following components in parts by weight: 50-90 parts of dimer acid, 5-40 parts of dicarboxylic acid, 45-130 parts of diamine, 1-10 parts of a catalyst and 5-20 parts of an antioxidant. The polyamide hot melt adhesive disclosed by the invention has relatively high softening point and melt viscosity, the adhesive property of the polyamide hot melt adhesive can be improved, and the polyamide hot melt adhesive has relatively high tensile strength and elongation at break, so that the polyamide hot melt adhesive is excellent in mechanical property and relatively wide in application range.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to a dimer acid type polyamide hot melt adhesive and a preparation method thereof. Background Art

[0002] Hot melt adhesive is a solvent-free plastic adhesive that is solid at room temperature and can melt and flow at high temperature. It is applied to the surface of the substrate at high temperature and produces a bonding effect by cooling and solidification. The advantage of hot melt adhesive is that it does not require a solvent carrier as a mobile phase. After the adhesive film is formed on the surface of the substrate, it does not require drying treatment and can achieve rapid bonding by simply cooling. It greatly overcomes the potential hazards caused by the application of solvents in traditional adhesives and can also meet efficient production line operations and lower costs.

[0003] Polyamide is a hot melt adhesive with the best bonding performance. It can be divided into two categories: dimer acid type polyamide hot melt adhesive and nylon type polyamide hot melt adhesive. Dimer acid type polyamide hot melt adhesive is a dimer acid amide resin formed by the condensation of dimer acid and diamine or polyamine. It has the characteristics of narrow melting range, narrow softening point range, non-toxicity, good chemical resistance, etc. Nylon type polyamide hot melt adhesive adopts the preparation method of solution polymerization, and the post-treatment of solvent separation inevitably brings environmental pollution. Therefore, dimer acid type polyamide hot melt adhesive is the research focus and is widely reported.

[0004] However, the existing dimer acid-based polyamide hot melt adhesives in China still have problems such as low softening point and low melt viscosity, which result in poor bonding performance during application, and poor mechanical properties such as tensile strength, which limits the scope of application. Further improvements are needed to improve the performance of polyamide hot melt adhesives.

[0005] In view of the problems existing in the prior art, how to provide a dimer acid type polyamide hot melt adhesive so that the prepared polyamide hot melt adhesive has a higher softening point, melt viscosity, tensile strength and elongation at break, and has better bonding properties and mechanical properties is a problem to be solved urgently in the present invention. Summary of the invention

[0006] The object of the present invention is to provide a dimer acid type polyamide hot melt adhesive and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides a dimer acid type polyamide hot melt adhesive, characterized in that the raw materials for preparing the polyamide hot melt adhesive include the following components in parts by weight: 50-90 parts of dimer acid, 5-40 parts of dicarboxylic acid, 45-130 parts of diamine, 1-10 parts of catalyst, and 5-20 parts of antioxidant;

[0008] The diamine comprises an aliphatic diamine and 1,4-bis(4-aminophenyl)piperazine;

[0009] The catalyst is modified tetrabutyl titanate.

[0010] As a further improvement, the aliphatic diamine is at least one of ethylenediamine, hexamethylenediamine, pentamethylenediamine, di-tert-butylethylenediamine, 2-methylpentamethylenediamine, and dodecanediamine.

[0011] Preferably, the aliphatic diamine is hexamethylenediamine.

[0012] As a further improvement, the weight ratio of the aliphatic diamine to 1,4-bis(4-aminophenyl)piperazine is 2-5:1.

[0013] As a further improvement, the modified tetrabutyl titanate is prepared from nano silicon dioxide, a coupling agent and tetrabutyl titanate.

[0014] As a further improvement, the synthesis of the modified tetrabutyl titanate comprises the following steps:

[0015] (1) drying the nano-silica in vacuum at 120° C. for 12 h, then adding the dried nano-silica, oleic acid and an organic solvent into a flask, ultrasonically shaking and stirring for 10-30 min, then adding a titanate coupling agent, continuing to stir for 30-60 min, and post-treating to obtain modified nano-silica;

[0016] (2) adding the modified nano-silica and tetrabutyl titanate obtained in step (1) into an organic solvent, mixing by ultrasonic vibration for 30-60 minutes, and post-treating to obtain modified tetrabutyl titanate.

[0017] As a further improvement, the weight ratio of the modified nano-silicon dioxide to tetrabutyl titanate is 1.5-3:1.

[0018] As a further improvement, the dimer acid is C 16 -C 20 The dimer acid derived from unsaturated fatty acid is at least one selected from the group consisting of dimer acids derived from oleic acid, linoleic acid, elaidic acid, ricinoleic acid and linolenic acid.

[0019] Preferably, the dimer acid is a dimer acid derived from ricinoleic acid, and more preferably, the dimer acid is dimerized ricinoleic acid.

[0020] As a further improvement, the dicarboxylic acid is at least one of adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, isophthalic acid, and terephthalic acid.

[0021] Preferably, the dicarboxylic acid is adipic acid.

[0022] As a further improvement, the antioxidant is at least one of tris(2,4-di-tert-butyl)phenyl phosphite, distearyl pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol.

[0023] Preferably, the antioxidant is octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0024] The present invention provides a method for preparing a dimer acid type polyamide hot melt adhesive, which is characterized by comprising the following steps:

[0025] (1) Add dimer acid, dicarboxylic acid and catalyst into a flask, stir and heat to 160-180°C, then add diamine and antioxidant in batches, and continue stirring and mixing for 40-60 minutes;

[0026] (2) Raising the temperature to 200-240° C. to carry out polymerization reaction for 3-4 hours, and after the reaction is completed, post-processing is performed to obtain a dimer acid type polyamide hot melt adhesive.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The invention provides a dimer acid type polyamide hot melt adhesive and a preparation method thereof, so that the prepared polyamide hot melt adhesive has a higher softening point and melt viscosity, indicating excellent bonding performance, and has higher tensile strength and elongation at break, indicating excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the infrared spectrum of the dimer acid type polyamide hot melt adhesive prepared in Example 4; DETAILED DESCRIPTION

[0030] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0031] In the following examples, except for the modified tetrabutyl titanate, the other compound monomers and related reagents used can be purchased from the market, among which nano-silicon dioxide (particle size of 20 nm) was purchased from Nanjing Tianxing New Materials Co., Ltd., model TSP-H10, and dimerized ricinoleic acid was purchased from Shandong Binzhou Jinsheng New Materials Technology Co., Ltd., model L20.

[0032] The synthesis of modified tetrabutyl titanate comprises the following steps:

[0033] (1) The nano-silica was vacuum dried at 120° C. for 12 h, and then 1 g of the dried nano-silica, 10 mL of oleic acid and 300 mL of toluene were added to a flask, ultrasonically dispersed and stirred for 30 min, and then 0.1 g of isopropyl titanate triisostearate was added thereto, and stirring was continued for 40 min. After the reaction was completed, the toluene was removed by rotary evaporation, and the obtained solid was dissolved in 20 mL of ether and centrifuged to remove the upper liquid, and the reaction was repeated 3 times. The obtained lower layer was dried at 70° C. for 12 h to obtain modified nano-silica;

[0034] (2) 0.4 g of modified nano-silica and 0.2 g of tetrabutyl titanate were added to 200 mL of anhydrous toluene, ultrasonically dispersed and stirred for 60 min. After the reaction was completed, the mixture was filtered and the obtained solid was dried at 120° C. for 3 h to obtain modified tetrabutyl titanate.

[0035] The preparation methods of Examples 1-4 and Comparative Examples 1-5 comprise the following steps:

[0036] (1) Add dimer acid, dicarboxylic acid and catalyst into a flask, stir and heat to 160°C, then add diamine in three batches, stir and mix at 160°C for 60 minutes at a stirring speed of 300 rpm;

[0037] (2) The temperature was raised to 230° C. and the polymerization reaction was carried out for 3 h. After the reaction was completed, the sample was polymerized under vacuum for 50 min to obtain a yellow viscous liquid. The sample was cooled to 160° C. to complete the discharge, and a dimer acid type hot melt adhesive was obtained.

[0038] The components and contents used in Examples 1-4 and Comparative Examples 1-5 are shown in Table 1-2 below:

[0039] Table 1

[0040]

[0041]

[0042] Table 2

[0043]

[0044] The dimer acid type polyamide hot melt adhesives prepared in Examples 1-4 and Comparative Examples 1-5 were tested for softening point, melt viscosity, tensile strength, and elongation at break. The test methods are as follows:

[0045] Softening point: Tested according to GB / T 15332-1994 standard;

[0046] Melt viscosity: tested according to GB / T 2794-1995 standard, the test temperature is 190℃;

[0047] Tensile strength: tested according to GB / T 528 standard;

[0048] Elongation at break: Tested in accordance with GB / T 528 standard.

[0049] The test results are shown in Table 3, as follows:

[0050] Table 3

[0051] Softening point / ℃ Melt viscosity / mPa Tensile strength / MPa Elongation at break / % Example 1 163 4300 8.9 660 Example 2 168 4570 9.2 640 Example 3 174 4850 11.7 650 Example 4 170 4630 10.8 630 Comparative Example 1 132 3100 5.3 390 Comparative Example 2 136 3500 5.7 410 Comparative Example 3 141 3900 6.0 440 Comparative Example 4 155 4260 7.1 530 Comparative Example 5 147 4100 6.5 580

[0052] It can be seen from Example 3 and Comparative Examples 1-2 in Table 2 that, compared with the polyamide hot melt adhesive prepared by using only hexamethylenediamine or only 1,4-bis(4-aminophenyl)piperazine as the diamine, the polyamide hot melt adhesive prepared by using hexamethylenediamine and 1,4-bis(4-aminophenyl)piperazine as the diamine has a higher softening point and melt viscosity, indicating that the bonding performance is excellent, the tensile strength is higher and the elongation at break also reaches a higher balance, indicating that the mechanical properties of the polyamide hot melt adhesive are excellent.

[0053] It can be seen from Example 3 and Comparative Example 3 that compared with the polyamide hot melt adhesive prepared using hexamethylenediamine and benzidine as diamines, the polyamide hot melt adhesive prepared using hexamethylenediamine and 1,4-bis(4-aminophenyl)piperazine as diamines has a higher softening point and melt viscosity, indicating excellent bonding performance, and has higher tensile strength and elongation at break, indicating that the polyamide hot melt adhesive has excellent mechanical properties.

[0054] It can be seen from Example 3 and Comparative Example 4 that when the weight ratio of aliphatic diamine to 1,4-bis(4-aminophenyl)piperazine is within an appropriate range, the prepared polyamide hot melt adhesive has a higher softening point and melt viscosity, and can improve the tensile strength and elongation at break to a certain extent, indicating that its bonding properties and mechanical properties are excellent.

[0055] It can be seen from Example 3 and Comparative Example 5 that compared with the polyamide hot melt adhesive prepared using unmodified tetrabutyl titanate, the polyamide hot melt adhesive prepared using modified tetrabutyl titanate has a higher softening point, melt viscosity, tensile strength and elongation at break, indicating that its bonding properties and mechanical properties are both excellent.

[0056] It can be seen from the test results of Examples 1-4 that the polyamide hot melt adhesive prepared by the preparation method provided by the present invention has a higher softening point and melt viscosity, indicating that the bonding performance is excellent, the tensile strength is high and the elongation at break can be improved to a certain extent, indicating that the mechanical properties are excellent, and the application range of the polyamide hot melt adhesive can be broadened. Figure 1 It can be seen that the synthesis of the polyamide hot melt adhesive obtained in Example 4 is successful. Figure 1The infrared test conditions of the infrared spectrum are: Fourier transform infrared spectrometer, using ATR (attenuated total reflection) method for infrared characterization, scanning range 450cm -1 -4000cm -1 , resolution 2cm -1 , scan times 16 times.

[0057] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, 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 dimer acid type polyamide hot melt adhesive, characterized in that: The raw materials for preparing the polyamide hot melt adhesive include the following components in parts by weight: 50-90 parts of dimer acid, 5-40 parts of dicarboxylic acid, 45-130 parts of diamine, 1-10 parts of catalyst, and 5-20 parts of antioxidant; The diamine comprises an aliphatic diamine and 1,4-bis(4-aminophenyl)piperazine; The catalyst is modified tetrabutyl titanate.

2. A dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The aliphatic diamine is at least one of ethylenediamine, pentanediamine, hexamethylenediamine, di-tert-butylethylenediamine, 2-methylpentanediamine, and dodecanediamine.

3. A dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The weight ratio of the aliphatic diamine to 1,4-bis(4-aminophenyl)piperazine is 2-5:

1.

4. The dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The modified tetrabutyl titanate is prepared from nano silicon dioxide, a coupling agent and tetrabutyl titanate.

5. The dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The synthesis of the modified tetrabutyl titanate comprises the following steps: (1) drying the nano-silica in vacuum at 120° C. for 12 h, then adding the dried nano-silica, oleic acid and an organic solvent into a flask, ultrasonically shaking and stirring for 10-30 min, then adding a titanate coupling agent, continuing to stir for 30-60 min, and post-treating to obtain modified nano-silica; (2) adding the modified nano-silica and tetrabutyl titanate obtained in step (1) into an organic solvent, mixing by ultrasonic vibration for 30-60 minutes, and post-treating to obtain modified tetrabutyl titanate.

6. A dimer acid type polyamide hot melt adhesive according to claim 5, characterized in that: The weight ratio of the modified nano-silica to tetrabutyl titanate in the step (2) is 1.5-3:

1.

7. The dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The dimer acid is C 16 -C 20 Dimer acids derived from unsaturated fatty acids.

8. The dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The dicarboxylic acid is at least one of adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, isophthalic acid, and terephthalic acid.

9. The dimer acid type polyamide hot melt adhesive according to claim 1, characterized in that: The antioxidant is at least one of tris(2,4-di-tert-butyl)phenyl phosphite, distearyl pentaerythritol diphosphite, 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

10. A method for preparing a dimer acid type polyamide hot melt adhesive according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Add dimer acid, dicarboxylic acid and catalyst into a flask, stir and heat to 160-180°C, then add diamine and antioxidant in batches, and continue stirring and mixing for 40-60 minutes; (2) Raising the temperature to 200-240° C. for polymerization reaction for 3-5 hours, and after the reaction is completed, post-processing is performed to obtain a dimer acid type polyamide hot melt adhesive.

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