A kind of multi-component hot melt adhesive based on polyolefin and preparation method thereof

Abstract

The invention discloses a multi-component hot melt adhesive based on polyolefin and a preparation method thereof. The components of the hot melt adhesive include the following raw materials: polyolefin resin, high temperature resistant stabilizer, functionalized phenolic resin, tackifying resin, wax, and initiator. The polyolefin resin is used as a matrix material, has good bonding strength, and has a light odor during use. However, the traditional polyolefin hot melt adhesive has poor high temperature resistance and antioxidant properties and is greatly affected by temperature. In a high temperature environment, it is easy to fail in bonding. Therefore, the invention prepares a hot melt adhesive with excellent high temperature resistance and antioxidant properties by adding a high temperature resistant stabilizer and a functionalized phenolic resin into a polyolefin matrix. The hot melt adhesive can be used for bonding various parts of electronic components in electronic products, and has broad application prospects.

Description

Technical Field

[0001] The invention relates to the field of hot melt adhesives, in particular to a polyolefin-based multi-component hot melt adhesive and a preparation method thereof. Background Art

[0002] With the development of modern society, electronic products have become an indispensable part of people's lives, and the performance of electronic products has also attracted much attention. The bonding of various parts of electronic components in electronic products also has a great impact on the performance of electronic products. Hot melt adhesive is generally used to bond various parts of electronic components. Hot melt adhesive is an adhesive that does not require solvents. It is solid at room temperature and melts into liquid after heating. After wetting the adherend, it is pressed and cooled, and it quickly solidifies in a very short time to complete the bonding. Compared with other adhesives, hot melt adhesive has the advantages of easy synthesis, short curing time, wide bonding range, convenient storage and transportation, and no pollution to the environment. It conforms to the concept of green chemistry and is an environmentally friendly and non-toxic chemical product.

[0003] Hot melt adhesives can be divided into polyamide, polyurethane, polyester, polyolefin, etc. according to the different base polymers used. Polyolefin hot melt adhesives have good bonding strength, light odor during use, and will not have adverse effects on the human body. However, traditional polyolefin hot melt adhesives have poor antioxidant properties and are greatly affected by temperature. They have poor heat resistance and are prone to bonding failure in high temperature environments. Therefore, polyolefin hot melt adhesives need to be further improved to enhance high temperature resistance and antioxidant properties.

[0004] The patent with publication number CN110437795B discloses a hot melt adhesive and a preparation method thereof. The hot melt adhesive is mainly obtained by copolymerizing a non-hydroxyl-terminated polyolefin resin, a tackifying resin, an antioxidant and / or a catalyst, an isocyanate and a hydroxyl-terminated polyolefin resin. The invented hot melt adhesive has excellent waterproof properties and can be used for bonding various parts of electronic product components. However, the patent still has defects in actual application. The patent does not take into account that electronic equipment will continue to emit heat for a long time during operation and is more likely to generate heat in a high temperature environment. The hot melt adhesive is in a high temperature environment for a long time and is affected by the high temperature and has poor heat resistance, resulting in bonding failure, which reduces the service life of the hot melt adhesive. To this end, the present invention provides a multi-component hot melt adhesive based on polyolefin, which can be used for bonding various parts of electronic components in electronic products. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-component hot melt adhesive based on polyolefin and a preparation method thereof, so as to solve the following technical problems:

[0006] (1) Solved the problem of poor high temperature resistance of polyolefin resins;

[0007] (2) Solved the problem of poor antioxidant performance of polyolefin resins.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A polyolefin-based multi-component hot melt adhesive comprises the following raw materials in parts by weight: 80-100 parts of polyolefin resin, 2-6 parts of high temperature resistant stabilizer, 1-4 parts of functionalized phenolic resin, 15-25 parts of tackifying resin, 5-10 parts of wax, and 1-3 parts of initiator.

[0010] Furthermore, the polyolefin resin is one or more of amorphous poly-alpha-olefin resin, ethylene-butene copolymer, and ethylene-octene copolymer.

[0011] Furthermore, the preparation method of the high temperature resistant stabilizer is as follows:

[0012] Dissolve the halogenated butyl rubber in chloroform to form a reaction solution, add 2-(4-aminophenyl)-5-aminobenzoxazole to N,N-dimethylacetamide, stir until completely dissolved, add to the reaction solution, introduce nitrogen, heat to 50-60°C, add an acid binding agent, stir for 2-4 hours, separate, wash and dry to obtain a high temperature resistant stabilizer.

[0013] By adopting the above scheme, under the action of the acid binding agent, the active halogen substituent in the halogenated butyl rubber reacts with the amino group in the 2-(4-aminophenyl)-5-aminobenzoxazole structure to introduce a rigid oxazole aromatic ring to obtain a high temperature resistant stabilizer.

[0014] Furthermore, the halogenated butyl rubber is chlorinated butyl rubber or brominated butyl rubber.

[0015] Furthermore, the acid binding agent is pyridine or triethylamine.

[0016] Furthermore, the preparation method of the functionalized phenolic resin comprises the following steps:

[0017] Step 1, taking a phenolic resin and stirring it until it is dissolved in dimethyl sulfoxide, introducing nitrogen, adding 4-chloropropionic acid and an alkaline catalyst, raising the temperature to 110-115° C., and keeping the temperature for reaction for 2-4 hours to obtain a modified phenolic resin;

[0018] Step 2: Stir the modified phenolic resin until it is dissolved in toluene, add the hindered phenol compound and p-toluenesulfonic acid, raise the temperature to 90-105°C, react for 4-6 hours, and obtain the functionalized phenolic resin.

[0019] By adopting the above scheme, under the action of an alkaline catalyst, the active hydroxyl group in the phenolic resin structure undergoes a substitution reaction with the chlorine substituent in 4-chloropropionic acid, and an active carboxyl group is introduced to obtain a modified phenolic resin. Under the action of p-toluenesulfonic acid, the active carboxyl group in the modified phenolic resin can undergo an esterification reaction with the alcoholic hydroxyl group in the hindered phenolic compound to obtain a functionalized phenolic resin.

[0020] Furthermore, in step 1, the alkaline catalyst is anhydrous potassium carbonate or anhydrous sodium carbonate.

[0021] Furthermore, in step 2, the hindered phenol compound is 3,5-di-tert-butyl-4-hydroxybenzyl alcohol.

[0022] Furthermore, the tackifying resin is hydrogenated C5 petroleum resin or hydrogenated C9 petroleum resin; the wax is one or more of paraffin wax, Fischer-Tropsch wax or Sasol wax; and the initiator is one of diisopropylbenzene peroxide, benzoyl peroxide, lauric acid peroxide and tert-butyl perbenzoate.

[0023] A method for preparing a polyolefin-based multi-component hot melt adhesive comprises the following steps:

[0024] The first step is to put wax, high temperature stabilizer and functionalized phenolic resin into a reactor, stir and heat to 150-200°C;

[0025] The second step is to add polyolefin resin, vacuum and stir for 30-60 minutes at a stirring speed of 80-120r / min. After the polyolefin resin is completely dissolved, add tackifying resin and initiator, keep warm, vacuum and stir for 1-2 hours, and discharge the material to obtain polyolefin hot melt adhesive after mixing evenly without bubbles.

[0026] Beneficial effects of the present invention:

[0027] (1) The high temperature resistant stabilizer with a rigid oxazole aromatic ring prepared by the present invention can be cross-linked with a polyolefin matrix under the action of an initiator, so that the molecular chain of the polyolefin matrix has a higher density, the thermal motion of the molecular chain is suppressed, and the high temperature resistance of the polyolefin hot melt adhesive is improved, so as to avoid the polyolefin hot melt adhesive being in a high temperature environment for a long time, resulting in a decrease in the bonding performance. At the same time, the halogenated butyl rubber in the high temperature resistant stabilizer improves the toughness of the polyolefin hot melt adhesive, which can prevent the polyolefin hot melt adhesive from cracking or even falling off in a low temperature environment, thereby shortening the life of the polyolefin hot melt adhesive and no longer being tightly bonded to electronic components, thereby avoiding affecting the performance of electronic equipment.

[0028] (2) The functionalized phenolic resin prepared by the present invention has a macromolecular structure, is not easy to volatilize or migrate, can play a role in the polyolefin matrix for a long time, enhance the antioxidant properties of the polyolefin hot melt adhesive, and extend the service life of the polyolefin hot melt adhesive. At the same time, the phenolic resin in the functionalized phenolic resin is added to the polyolefin resin to enhance the fluidity of the polyolefin hot melt adhesive, increase the melt index, improve the wire drawing phenomenon of the hot melt adhesive, and avoid leaving glue marks on the surface of the bonded material, which affects the aesthetics and bonding strength.

[0029] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0031] Figure 1 The infrared spectra of the modified phenolic resin and the functionalized phenolic resin prepared in Example 1 of the present invention are shown. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] 1. Preparation of high temperature resistant stabilizer

[0035] 3.5 g of brominated butyl rubber was dissolved in chloroform to form a reaction solution, 0.6 g of 2-(4-aminophenyl)-5-aminobenzoxazole was added to N,N-dimethylacetamide, and stirred until completely dissolved. The mixture was added to the reaction solution, nitrogen was introduced, the temperature was raised to 55°C, 0.1 g of triethylamine was added, and the mixture was stirred for 3 h, separated, washed, and dried to obtain a high temperature resistant stabilizer.

[0036] The nitrogen content of the high temperature resistant stabilizer was determined using a Vario ELⅢ element analyzer produced by Elementary Company of Germany. The test showed that the nitrogen content of the high temperature resistant stabilizer was 2.14%. It can be seen that the amino group in 2-(4-aminophenyl)-5-aminobenzoxazole reacted with the active substituted bromine in the structure of brominated butyl rubber to provide a nitrogen source.

[0037] 2. Preparation of functionalized phenolic resin

[0038] Step 1: Take 4.2 g of phenolic resin and stir until dissolved in dimethyl sulfoxide, introduce nitrogen, add 0.4 g of 4-chloropropionic acid and 0.1 g of anhydrous potassium carbonate, raise the temperature to 115° C., and keep the temperature for 3 hours to obtain a modified phenolic resin;

[0039] Step 2: Stir 3.2 g of modified phenolic resin until dissolved in toluene, add 1 g of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and 0.5 g of p-toluenesulfonic acid, raise the temperature to 100° C., react for 5 h, and obtain a functionalized phenolic resin.

[0040] The sample was prepared by potassium bromide tablet method, and infrared test of high temperature resistant additives was carried out by Fourier infrared spectrometer, such as Figure 1 As shown, the spectral wavenumber test range is 4000cm -1 -500cm -1 , analysis shows that in the infrared spectrum of modified phenolic resin, 3295cm -1 The absorption peak of hydroxyl group appeared at 3021cm -1 The absorption peak of the carbon-hydrogen bond on the benzene ring appeared at 1716 cm -1 The absorption peak of the carbon-oxygen double bond in the carboxyl group appears at 3304 cm -1 The absorption peak of hydroxyl group appeared at 1735cm -1 The absorption peak of ester group appeared at 1712cm -1 The absorption peak of the carbon-oxygen double bond appears at , which is the absorption peak of the carbon-oxygen double bond in the carboxyl group that has not reacted completely.

[0041] 3. Preparation of polyolefin hot melt adhesive

[0042] The first step is to put 5g of Fischer-Tropsch wax, 2g of high temperature stabilizer and 1g of functionalized phenolic resin into a reactor, stir and heat to 150°C;

[0043] The second step is to add 80g of amorphous polyalphaolefin resin, vacuum stir for 30min, and the stirring speed is 80r / min. After the amorphous polyalphaolefin resin is completely melted, add 15g of hydrogenated C5 petroleum resin and 1g of diisophenylene peroxide, keep warm, vacuum stir for 1h, and mix evenly without bubbles to obtain polyolefin hot melt adhesive.

[0044] Example 2

[0045] Preparation of polyolefin hot melt adhesive

[0046] Step 1: put 6g of Fischer-Tropsch wax, 3g of high temperature stabilizer and 2g of functionalized phenolic resin into a reactor, stir and heat to 160°C;

[0047] The second step is to add 85g of amorphous polyalphaolefin resin, vacuum stir for 40min, and the stirring speed is 90r / min. After the amorphous polyalphaolefin resin is completely melted, add 20g of hydrogenated C5 petroleum resin and 2g of diisophenylene peroxide, keep warm, vacuum stir for 1.5h, and mix evenly without bubbles to obtain polyolefin hot melt adhesive.

[0048] The preparation method of the high temperature resistant stabilizer and the preparation method of the functionalized phenolic resin are the same as those in Example 1.

[0049] Example 3

[0050] Preparation of polyolefin hot melt adhesive

[0051] Step 1: put 7g of Fischer-Tropsch wax, 4g of high temperature stabilizer and 3g of functionalized phenolic resin into a reactor, stir and heat to 170°C;

[0052] The second step is to add 90g amorphous polyalphaolefin resin, vacuum stir for 50min, and the stirring speed is 100r / min. After the amorphous polyalphaolefin resin is completely melted, add 20g hydrogenated carbon 5 petroleum resin and 3g diisophenylene peroxide, keep warm, vacuum stir for 1.5h, mix evenly without bubbles, and then discharge the material to obtain polyolefin hot melt adhesive.

[0053] The preparation method of the high temperature resistant stabilizer and the preparation method of the functionalized phenolic resin are the same as those in Example 1.

[0054] Example 4

[0055] Preparation of polyolefin hot melt adhesive

[0056] Step 1: put 8g of Fischer-Tropsch wax, 5g of high temperature stabilizer and 4g of functionalized phenolic resin into a reactor, stir and heat to 180°C;

[0057] The second step is to add 95g of amorphous polyalphaolefin resin, vacuum stir for 60min, and the stirring speed is 110r / min. After the amorphous polyalphaolefin resin is completely melted, add 25g of hydrogenated C5 petroleum resin and 3g of diisophenylene peroxide, keep warm, vacuum stir for 2h, mix evenly without bubbles, and then discharge the material to obtain polyolefin hot melt adhesive.

[0058] The preparation method of the high temperature resistant stabilizer and the preparation method of the functionalized phenolic resin are the same as those in Example 1.

[0059] Comparative Example 1

[0060] Preparation of polyolefin hot melt adhesive

[0061] Step 1: Add 6 g of Fischer-Tropsch wax and 2 g of functionalized phenolic resin into a reactor, stir, and heat to 160°C;

[0062] The second step is to add 85g of amorphous polyalphaolefin resin, vacuum stir for 40min, and the stirring speed is 90r / min. After the amorphous polyalphaolefin resin is completely melted, add 20g of hydrogenated C5 petroleum resin and 2g of diisophenylene peroxide, keep warm, vacuum stir for 1.5h, and mix evenly without bubbles to obtain polyolefin hot melt adhesive.

[0063] The preparation method of the functionalized phenolic resin is the same as that in Example 1.

[0064] Comparative Example 2

[0065] Preparation of polyolefin hot melt adhesive

[0066] Step 1: Add 6g of Fischer-Tropsch wax and 3g of high temperature stabilizer into a reactor, stir, and heat to 160°C;

[0067] The second step is to add 85g of amorphous polyalphaolefin resin, vacuum stir for 40min, and the stirring speed is 90r / min. After the amorphous polyalphaolefin resin is completely melted, add 20g of hydrogenated C5 petroleum resin and 2g of diisophenylene peroxide, keep warm, vacuum stir for 1.5h, and mix evenly without bubbles to obtain polyolefin hot melt adhesive.

[0068] The preparation method of the high temperature resistant stabilizer is the same as that in Example 1.

[0069] Comparative Example 3

[0070] Preparation of polyolefin hot melt adhesive

[0071] Step 1: put 6g of Fischer-Tropsch wax, 3g of brominated butyl rubber and 2g of functionalized phenolic resin into a reactor, stir and heat to 160°C;

[0072] The second step is to add 85g of amorphous polyalphaolefin resin, vacuum stir for 40min, and the stirring speed is 90r / min. After the amorphous polyalphaolefin resin is completely melted, add 20g of hydrogenated C5 petroleum resin and 2g of diisophenylene peroxide, keep warm, vacuum stir for 1.5h, and mix evenly without bubbles to obtain polyolefin hot melt adhesive.

[0073] The preparation method of the functionalized phenolic resin is the same as that in Example 1.

[0074] Comparative Example 4

[0075] Preparation of polyolefin hot melt adhesive

[0076] Step 1: Add 6g of Fischer-Tropsch wax, 3g of high temperature stabilizer and 2g of phenolic resin into a reactor, stir and heat to 160°C;

[0077] The second step is to add 85g of amorphous polyalphaolefin resin, vacuum stir for 40min, and the stirring speed is 90r / min. After the amorphous polyalphaolefin resin is completely melted, add 20g of hydrogenated C5 petroleum resin and 2g of diisophenylene peroxide, keep warm, vacuum stir for 1.5h, and mix evenly without bubbles to obtain polyolefin hot melt adhesive.

[0078] The preparation method of the high temperature resistant stabilizer is the same as that in Example 1.

[0079] Performance Testing

[0080] Performance test of polyolefin-based multi-component hot melt adhesives prepared in Examples 1 to 4 of the present invention and Comparative Examples 1 to 4:

[0081] The polyolefin hot melt adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were cured for 1 day to prepare adhesive film samples; the elongation at break of the polyolefin hot melt adhesive was tested according to GB / T 1040.3-2006 standard; the molten polyolefin hot melt adhesive was poured into the barrel of a melt index tester, and then pressed down with a punch weighing 2160±10g, and the number of grams of the adhesive liquid squeezed out of the small hole at the bottom of the barrel within 10 minutes was measured to test its melt index and determine the fluidity of the polyolefin hot melt adhesive; the polyolefin hot melt adhesive was placed on a stainless steel plate, and after curing for 24 hours, the peel strength of the polyolefin hot melt adhesive was tested according to GB / T 2792-2014 standard; the polyolefin hot melt adhesive was placed on a stainless steel plate, and after curing for 1 day, it was placed in an accelerated aging box, the temperature was set at 150°C, and it was taken out after 2 days to test the peel strength after aging to determine the antioxidant performance of the polyolefin hot melt adhesive; according to GB / T 16998-1997 standard, put the film sample at 200℃ for 5 days and then take it out to observe the phenomenon of the film sample to judge the high temperature resistance of polyolefin hot melt adhesive. The test results are shown in the table below:

[0082]

[0083] It can be seen from the above table that the polyolefin-based multi-component hot melt adhesives prepared in Examples 1 to 4 have excellent high temperature resistance and antioxidant properties, among which the test result of Example 2 is the best. Comparative Example 1 does not add a high temperature stabilizer, and the hot melt adhesive turns brown, smokes and gels because the modified brominated butyl rubber with a rigid oxazole aromatic ring is not added, resulting in poor high temperature resistance. Comparative Example 2 does not add a functionalized phenolic resin, and the peel strength after thermal aging decreases significantly because it is impossible to utilize the modified phenolic resin to graft hindered phenolic compounds to inhibit and decompose peroxide free radicals, resulting in poor antioxidant properties. Comparative Example 3 adds brominated butyl rubber, which can enhance the toughness of the polyolefin matrix to a certain extent. Comparative Example 4 adds phenolic resin, which enhances the fluidity of the polyolefin hot melt adhesive to a certain extent and improves the melt index.

[0084] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A multi-component hot melt adhesive based on polyolefin, characterized in that: The method comprises the following raw materials in parts by weight: 80-100 parts of polyolefin resin, 2-6 parts of high temperature stabilizer, 1-4 parts of functionalized phenolic resin, 15-25 parts of tackifying resin, 5-10 parts of wax, and 1-3 parts of initiator; The preparation method of the high temperature resistant stabilizer is as follows: Dissolve the halogenated butyl rubber in chloroform to form a reaction solution, add 2-(4-aminophenyl)-5-aminobenzoxazole to N,N-dimethylacetamide, stir until completely dissolved, add to the reaction solution, introduce nitrogen, heat to 50-60°C, add an acid binding agent, stir for 2-4 hours, separate, wash and dry to obtain a high temperature resistant stabilizer; The preparation method of the functionalized phenolic resin comprises the following steps: Step 1, taking a phenolic resin and stirring it until it is dissolved in dimethyl sulfoxide, introducing nitrogen, adding 4-chloropropionic acid and an alkaline catalyst, raising the temperature to 110-115° C., and keeping the temperature for reaction for 2-4 hours to obtain a modified phenolic resin; Step 2: Stir the modified phenolic resin until it is dissolved in toluene, add the hindered phenol compound and p-toluenesulfonic acid, raise the temperature to 90-105° C., and react for 4-6 hours to obtain a functionalized phenolic resin.

2. A polyolefin-based multi-component hot melt adhesive according to claim 1, characterized in that: The polyolefin resin is one or more of amorphous poly-alpha-olefin resin, ethylene-butene copolymer, and ethylene-octene copolymer.

3. The polyolefin-based multi-component hot melt adhesive according to claim 1, characterized in that: The halogenated butyl rubber is chlorinated butyl rubber or brominated butyl rubber.

4. The polyolefin-based multi-component hot melt adhesive according to claim 1, characterized in that: The acid binding agent is pyridine or triethylamine.

5. The polyolefin-based multi-component hot melt adhesive according to claim 1, characterized in that: In step 1, the alkaline catalyst is anhydrous potassium carbonate or anhydrous sodium carbonate.

6. The polyolefin-based multi-component hot melt adhesive according to claim 1, characterized in that: In step 2, the hindered phenol compound is 3,5-di-tert-butyl-4-hydroxybenzyl alcohol.

7. The polyolefin-based multi-component hot melt adhesive according to claim 1, characterized in that: The tackifying resin is hydrogenated C5 petroleum resin or hydrogenated C9 petroleum resin; the wax is one or more of paraffin wax, Fischer-Tropsch wax or Sasol wax; the initiator is one of diisopropylbenzene peroxide, benzoyl peroxide, lauric acid peroxide and tert-butyl perbenzoate.

8. A method for preparing a polyolefin-based multi-component hot melt adhesive as claimed in claim 1, characterized in that: The following steps are involved: The first step is to put wax, high temperature stabilizer and functionalized phenolic resin into a reactor, stir and heat to 150-200°C; The second step is to add polyolefin resin, vacuum and stir for 30-60 minutes at a stirring speed of 80-120r / min. After the polyolefin resin is completely melted, add tackifying resin and initiator, keep warm, vacuum and stir for 1-2 hours, and discharge the material to obtain polyolefin hot melt adhesive after mixing evenly without bubbles.

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