阅读说明：本技术 一种满足喷涂工艺的阻燃热熔胶及其制备方法 (Flame-retardant hot melt adhesive meeting spraying process and preparation method thereof ) 是由 余俊良 韦宝平 曹少波 吴永升 于 2020-07-23 设计创作，主要内容包括：本发明公开了一种满足喷涂工艺的阻燃热熔胶及其制备方法,该阻燃热熔胶包括以下质量百分数计的组分：聚合物10-50％、增塑剂10-30％、增粘树脂30-70％、抗氧剂0.1-2％、液体阻燃剂为1-20％、硼酸锌单体接枝聚苯乙烯树脂0-10％,上述组分的质量百分比之和为100％。本发明制备的阻燃热熔胶具有较高的剥离力、较高的初粘力和对基材有良好的润湿性,同时还能通过UL-94阻燃性能测试,达到V-1阻燃等级。(The invention discloses a flame-retardant hot melt adhesive meeting a spraying process and a preparation method thereof, wherein the flame-retardant hot melt adhesive comprises the following components in percentage by mass: 10-50% of polymer, 10-30% of plasticizer, 30-70% of tackifying resin, 0.1-2% of antioxidant, 1-20% of liquid flame retardant and 0-10% of zinc borate monomer grafted polystyrene resin, wherein the sum of the mass percentages of the components is 100%. The flame-retardant hot melt adhesive prepared by the invention has higher peeling force, higher initial adhesion and good wettability to a base material, and can pass a UL-94 flame-retardant performance test to reach a V-1 flame-retardant grade.)

1. The flame-retardant hot melt adhesive meeting the spraying process is characterized by comprising the following components in percentage by mass: 10-50% of polymer, 10-30% of plasticizer, 30-70% of tackifying resin, 0.1-2% of antioxidant, 1-20% of liquid flame retardant and 0-10% of zinc borate monomer grafted polystyrene resin, wherein the sum of the mass percentages of the components is 100%.

2. The flame-retardant hot melt adhesive according to claim 1, wherein the polymer is selected from one or a mixture of two or more of styrene-isoprene-styrene, styrene-butadiene-styrene, hydrogenated styrene-butadiene block copolymer, maleic anhydride modified hydrogenated styrene-butadiene block copolymer, styrene-butadiene-butylene-styrene block copolymer, styrene-butadiene-styrene block copolymer, polyolefin, amorphous poly-alpha olefin, polyethylene homopolymer/copolymer, polypropylene homopolymer/copolymer, and ethylene-vinyl acetate.

3. The flame-retardant hot melt adhesive meeting the requirement of the spraying process as claimed in claim 1, wherein the plasticizer is one or a mixture of more than two of naphthenic oil, white oil, phthalate plasticizer, low molecular polybutadiene and halogen-free oligomeric phosphate.

4. The flame-retardant hot melt adhesive meeting the requirement of spraying process of claim 1, wherein the tackifying resin is one or a mixture of two or more of rosin resin, hydrogenated rosin resin, polymerized rosin resin, disproportionated rosin resin, C5 petroleum resin, hydrogenated DCPD petroleum resin, maleic anhydride modified rosin ester, C5/C9 copolymerized petroleum resin, terpene resin, modified terpene phenol resin, hydrogenated C5 petroleum resin and hydrogenated C9 petroleum resin.

5. The flame-retardant hot melt adhesive meeting the requirement of the spraying process according to claim 1, wherein the liquid flame retardant is one or a mixture of more than two of halogen-free phosphorus flame retardants, novel phosphorus flame retardants, bromine liquid flame retardants and liquid organosiloxane flame retardants; the halogen-free phosphorus flame retardant is selected from one of Doher 601, Doher 605 and Doher6209 in the chemical industry; the novel phosphorus series flame retardant is selected from Van field technology FT-707; the brominated liquid flame retardant is selected from Doher6206 in the chemical industry; the liquid organosiloxane flame retardant is selected from dow corning 40-00.

6. The flame-retardant hot melt adhesive meeting the spraying process of claim 1, wherein the zinc borate monomer grafted polystyrene resin is prepared by the following method:

1) treating the polystyrene resin by high-energy electron beam radiation; the conditions of the high-energy electron beam radiation treatment are as follows: the electron beam energy was 50kGy, 700keV, and the treatment time was 5 s;

2) adding the radiation-treated polystyrene resin obtained in the step 1) into an acetone/water solvent, sequentially adding a 1-hydroxycyclohexyl phenyl ketone photoinitiator and a zinc borate flame-retardant monomer, and performing ultraviolet radiation treatment; the conditions of the ultraviolet radiation treatment are as follows: the ultraviolet wavelength is 312nm, and the processing time is1 min; wherein the polystyrene resin is prepared from zinc borate flame-retardant monomer and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 100 (3-8) to 0.001-0.005;

3) purifying the sample subjected to ultraviolet radiation treatment obtained in the step 2) by using an ethanol solvent to finally obtain the zinc borate monomer grafted polystyrene resin.

7. The flame-retardant hot melt adhesive meeting the spraying process as claimed in claim 1, wherein the flame-retardant hot melt adhesive further comprises 0.5-5% by mass of a smoke suppressant.

8. A preparation method of a flame-retardant hot melt adhesive meeting a spraying process is characterized by comprising the following steps:

s1: confirming that a bottom valve of the reaction kettle is closed, opening steam for heating, starting a stirring paddle, and adding a plasticizer with a formula amount and an antioxidant with a formula amount;

s2: raising the temperature of the reaction kettle of S1 to 135-145 ℃, adding the polymer with the formula amount, and then stirring until the polymer is completely melted; after the polymer is completely melted, adding zinc borate monomer graft polystyrene resin with the formula amount, and stirring to completely melt the zinc borate monomer graft polystyrene resin;

s3: uniformly adding the tackifying resin with the formula amount into a reaction kettle of S2, stirring, adding the liquid flame retardant with the formula amount and the smoke suppressant with the formula amount after the tackifying resin is completely melted, and fully reacting;

s4: after the reaction in the S3 is finished, filtering the molten material in the reaction kettle;

s5: and (4) sequentially passing the molten material filtered in the step (S4) through a cooling system and a drying system, and finally packaging.

9. The method of claim 8, wherein in step S2, after the polymer is added, the mixture is stirred for 10-20min at a stirring speed of 50 rpm, the polymer on the wall of the reaction kettle and the stirring paddle is scraped by a scraper, the mixture is stirred continuously at a stirring speed of 50 rpm for 40-50min, whether the sample is completely melted or not is sampled, and if the particles still exist, the stirring is continued, and the extended stirring time is recorded.

10. The method as claimed in claim 8, wherein in step S3, after the material is completely added, the reaction kettle is evacuated to maintain the temperature in the reaction kettle at 135-145 ℃, and when the vacuum degree is above 0.07 and the material is not expanded, the reaction kettle is evacuated for 25-40 min.

Technical Field

The invention relates to a hot melt adhesive, in particular to a flame-retardant hot melt adhesive meeting a spraying process and a preparation method thereof.

Background

The hot melt adhesive is a plastic adhesive and belongs to an environment-friendly chemical product. In the field of industrial adhesives, hot melt adhesives are commonly used to bond together a wide variety of articles, including disposable absorbent articles having nonwoven substrates, building materials, electronic materials, and the like. The raw materials have flame retardant properties, most of hot melt adhesives in the prior art have no flame retardant properties, a small part of hot melt adhesives are matched by adding inorganic flame retardants and organic flame retardants to realize the flame retardant effect, but if the added inorganic flame retardants are required to achieve the required flame retardant effect, the addition amount of the inorganic flame retardants is very high, and the compatibility of the inorganic flame retardants and polymers is poor, so that the hot melt adhesives can be settled and layered, the adhesive machine is easy to block, and the hot melt adhesives are not suitable for spraying processes such as fiber spraying, spiral spraying and the like; and the inorganic flame retardant has great negative effect on the mechanical property of the hot melt adhesive and can reduce the initial adhesion and the peeling strength.

For example, the raw materials (PE film, polypropylene spunbonded fabric, composite nonwoven fabric, and spunlace fabric) of products such as disposable medical protective clothing, surgical gown, and fire protective clothing on the market at present all have flame retardant properties, the amount of adhesive used for bonding is small, the coating process requirement is high (the viscosity is not too high for spraying construction), and the existing flame retardant hot melt adhesive meeting the spraying process cannot meet the process requirement.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the flame-retardant hot melt adhesive meeting the requirement of a spraying process. The flame-retardant hot melt adhesive prepared by the invention has higher peeling force, higher initial adhesion and good wettability to a base material, and can pass a UL-94 flame-retardant performance test to reach a V-1 flame-retardant grade.

The second purpose of the invention is to provide a preparation method of the flame-retardant hot melt adhesive meeting the spraying process.

One of the purposes of the invention is realized by adopting the following technical scheme: the flame-retardant hot melt adhesive meeting the spraying process comprises the following components in percentage by mass: 10-50% of polymer, 10-30% of plasticizer, 30-70% of tackifying resin, 0.1-2% of antioxidant, 1-20% of liquid flame retardant and 0-10% of zinc borate monomer grafted polystyrene resin, wherein the sum of the mass percentages of the components is 100%.

Further the polymer is selected from one or a mixture of two or more of styrene-isoprene-styrene, styrene-butadiene-styrene, hydrogenated styrene-butadiene block copolymer, maleic anhydride modified hydrogenated styrene-butadiene block copolymer, styrene-butadiene-butylene-styrene block copolymer, styrene-butadiene-styrene block copolymer, polyolefin, amorphous poly-alpha-olefin, polyethylene homopolymer/copolymer, polypropylene homopolymer/copolymer or ethylene-vinyl acetate.

The plasticizer is one or a mixture of more than two of naphthenic oil, white oil, phthalate plasticizer, low molecular polybutadiene and halogen-free oligomeric phosphate.

Further, the tackifying resin is selected from one or a mixture of more than two of rosin resin, hydrogenated rosin resin, polymerized rosin resin, disproportionated rosin resin, C5 petroleum resin, hydrogenated DCPD petroleum resin, maleic anhydride modified rosin ester, C5/C9 copolymerized petroleum resin, terpene resin, modified terpene phenol resin, hydrogenated C5 petroleum resin and hydrogenated C9 petroleum resin.

Further, the liquid flame retardant is selected from one or a mixture of more than two of halogen-free phosphorus flame retardants, novel phosphorus flame retardants, bromine liquid flame retardants and liquid organosiloxane flame retardants; the halogen-free phosphorus flame retardant is selected from one of Doher 601, Doher 605 and Doher6209 in the chemical industry; the novel phosphorus series flame retardant is selected from Van field technology FT-707; the brominated liquid flame retardant is selected from Doher6206 in the chemical industry; the liquid organosiloxane flame retardant is selected from dow corning 40-00.

The zinc borate monomer grafted polystyrene resin is prepared by the following method:

1) treating the polystyrene resin by high-energy electron beam radiation; the conditions of the high-energy electron beam radiation treatment are as follows: the electron beam energy was 50kGy, 700keV, and the treatment time was 5 s;

2) adding the radiation-treated polystyrene resin obtained in the step 1) into an acetone/water solvent, sequentially adding a 1-hydroxycyclohexyl phenyl ketone photoinitiator and a zinc borate flame-retardant monomer, and performing ultraviolet radiation treatment; the conditions of the ultraviolet radiation treatment are as follows: the ultraviolet wavelength is 312nm, and the processing time is1 min; wherein the polystyrene resin is prepared from zinc borate flame-retardant monomer and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 100 (3-8) to 0.001-0.005;

3) purifying the sample subjected to ultraviolet radiation treatment obtained in the step 2) by using an ethanol solvent to finally obtain the zinc borate monomer grafted polystyrene resin.

The flame-retardant hot melt adhesive further comprises 0.5-5% of smoke suppressant in percentage by mass.

The second purpose of the invention is realized by adopting the following technical scheme: a preparation method of a flame-retardant hot melt adhesive meeting a spraying process comprises the following steps:

s1: confirming that a bottom valve of the reaction kettle is closed, opening steam for heating, starting a stirring paddle, and adding a plasticizer with a formula amount and an antioxidant with a formula amount;

s2: raising the temperature of the reaction kettle of S1 to 135-145 ℃, adding the polymer with the formula amount, and then stirring until the polymer is completely melted; after the polymer is completely melted, adding zinc borate monomer graft polystyrene resin with the formula amount, and stirring to completely melt the zinc borate monomer graft polystyrene resin;

s3: uniformly adding the tackifying resin with the formula amount into a reaction kettle of S2, stirring, adding the liquid flame retardant with the formula amount and the smoke suppressant with the formula amount after the tackifying resin is completely melted, and fully reacting;

s4: after the reaction in the S3 is finished, filtering the molten material in the reaction kettle;

s5: and (4) sequentially passing the molten material filtered in the step (S4) through a cooling system and a drying system, and finally packaging.

Further, in step S2, after the polymer is added, stirring for 10-20min at a stirring speed of 50 rpm, scraping the polymer off the wall of the reaction kettle and the stirring paddle with a scraper, and continuing stirring at a stirring speed of 50 rpm; and stirring for 40-50min, sampling whether the particles are completely molten, continuing stirring if the particles still exist, and recording the prolonged stirring time.

Further in step S3, after the material is added, the reaction kettle is vacuumized, the temperature in the reaction kettle is kept at 135-145 ℃, and when the vacuum degree is above 0.07 and the material is not expanded, the reaction kettle is vacuumized for 25-40 min.

Compared with the prior art, the invention has the beneficial effects that:

(1) the flame-retardant hot melt adhesive prepared by the invention has higher peeling force, higher initial adhesion and good wettability to a base material, and can pass a UL-94 flame-retardant performance test to reach a V-1 flame-retardant grade.

(2) The flame-retardant hot melt adhesive prepared by the invention can provide flame-retardant performance, and is more suitable for spraying compared with the flame-retardant hot melt adhesive in the market; the finished product prepared from the flame-retardant hot melt adhesive also has excellent flame-retardant performance;

(3) the flame-retardant hot melt adhesive prepared by the invention is compounded by adopting various liquid flame retardants, achieves the best flame-retardant performance, and is widely applied to the fields of building material bonding, electronic material bonding and the like.

Detailed Description

The present invention is further described below with reference to specific embodiments, and it should be noted that, without conflict, any combination between the embodiments or technical features described below may form a new embodiment.

In the present invention, all parts and percentages are by weight, unless otherwise specified, and the equipment and materials used may be commercially available. The methods in the following examples are conventional in the art unless otherwise specified.

The method comprises the following specific steps: the flame-retardant hot melt adhesive meeting the spraying process comprises the following components in percentage by mass: 10-50% of polymer, 10-30% of plasticizer, 30-70% of tackifying resin, 0.1-2% of antioxidant, 1-20% of liquid flame retardant and 0-10% of zinc borate monomer grafted polystyrene resin, wherein the sum of the mass percentages of the components is 100%.

As a further preferred embodiment, the polymer is selected from one or a mixture of two or more of styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), hydrogenated styrene-butadiene block copolymer (SEBS), maleic anhydride modified hydrogenated styrene-butadiene block copolymer, styrene-butadiene-butylene-styrene block copolymer (SBBS), styrene-butadiene-styrene block copolymer, polyolefin, amorphous poly-alpha olefin, polyethylene homopolymer/copolymer, polypropylene homopolymer/copolymer, or ethylene-vinyl acetate.

In the present embodiment, the styrene-isoprene-styrene (SIS) includes SIS1126 and SIS4019 of maoyangba toming huaxing petrochemical limited, SIS1220, SIS1300, and SIS1120 of santa polysachusei ltd; the styrene-butadiene-styrene (SBS) includes YH-791 and YH-792 of Yueyang Barlin Huaxing petrochemical Co., Ltd, D1102JS and D1155JOP of Corning USA; the polyolefin includes dow chemical W200. The most preferred polymers are the styrene-butadiene block copolymer YH-791 from Yueyang Barlin Huaxing petrochemical Co., Ltd and the ethylene-isoprene block copolymer SIS1220 from Shandong Polysanta Tech Co., Ltd, in a ratio of YH-791 to SIS1220 of 1: 3.

More preferably, the plasticizer is one or a mixture of two or more selected from naphthenic oil, white oil, phthalate plasticizer, low molecular polybutadiene (1,2-LPB), and halogen-free oligomeric phosphate. As most preferred plasticizers are naphthenic oils and halogen-free oligomeric phosphorus esters, naphthenic oils: the ratio of the halogen-free oligomeric phosphate ester is (4-6) to 1, and the most preferable combination ratio is 5 to 1.

As a further preferable mode, the tackifying resin is one or a mixture of two or more selected from rosin resin, hydrogenated rosin resin, polymerized rosin resin, disproportionated rosin resin, C5 petroleum resin, hydrogenated DCPD petroleum resin, maleic anhydride modified rosin ester, C5/C9 copolymerized petroleum resin, terpene resin, modified terpene phenol resin, hydrogenated C5 petroleum resin and hydrogenated C9 petroleum resin.

In the present embodiment, the hydrogenated C5 petroleum resin includes hydrogenated C5 petroleum resin available from eastman corporation; the hydrogenated DCPD petroleum resin comprises hydrogenated DCPD petroleum resin from Istmann; the hydrogenated C9 petroleum resin comprises hydrogenated C9 petroleum resin of Hebei Ming chemical engineering science and technology Limited; the maleic anhydride-modified rosin ester includes maleic anhydride-modified rosin ester of choma chemical industry ltd, guangxi; the most preferred tackifying resin is hydrogenated C5 petroleum resin from Istman.

As a further preferred embodiment, the antioxidant may be present in an amount of about 0.1% to about 2% by weight, and preferably in an amount of about 0.4% to about 2% by weight. Antioxidants help protect the above-noted adhesive components, and thus the entire adhesive system, from thermal and oxidative degradation that typically occurs during manufacture and application of the adhesive and that the final product is typically exposed to the ambient environment. Such degradation is often manifested by deterioration in the appearance, physical properties, and performance characteristics of the adhesive. Preferably, the antioxidant is selected from 1010 type antioxidant of Fushan Yuan Sheng chemical Co., Ltd and 168 type antioxidant of Fushan Yuan Sheng chemical Co., Ltd.

As a further preferable scheme, the liquid flame retardant is one or a mixture of more than two of halogen-free phosphorus flame retardants, novel phosphorus flame retardants, bromine liquid flame retardants and liquid organosiloxane flame retardants; the halogen-free phosphorus flame retardant is selected from one of Doher 601, Doher 605 and Doher6209 in the chemical industry; the novel phosphorus series flame retardant is selected from Van field technology FT-707; the brominated liquid flame retardant is selected from Doher6206 in the chemical industry; the liquid organosiloxane flame retardant is selected from dow corning 40-00.

As a further preferable scheme, the zinc borate monomer grafted polystyrene resin is prepared by the following method:

1) treating the polystyrene resin by high-energy electron beam radiation; the conditions of the high-energy electron beam radiation treatment are as follows: the electron beam energy was 50kGy, 700keV, and the treatment time was 5 s;

2) adding the radiation-treated polystyrene resin obtained in the step 1) into an acetone/water solvent, sequentially adding a 1-hydroxycyclohexyl phenyl ketone photoinitiator and a zinc borate flame-retardant monomer, and performing ultraviolet radiation treatment; the conditions of the ultraviolet radiation treatment are as follows: the ultraviolet wavelength is 312nm, and the processing time is1 min; wherein the polystyrene resin is prepared from zinc borate flame-retardant monomer and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 100 (3-8) to 0.001-0.005;

3) purifying the sample subjected to ultraviolet radiation treatment obtained in the step 2) by using an ethanol solvent to finally obtain the zinc borate monomer grafted polystyrene resin.

As a further preferable scheme, the flame-retardant hot melt adhesive also comprises 0.5-5% of smoke suppressant in percentage by mass. The smoke suppressant can be one or a mixture of more than two of Doher-103 produced by Dongguan new material science and technology company Limited and Charmax FS-BZMA produced by Angrdan chemical industry Limited.

As a further preferable scheme, the flame-retardant hot melt adhesive further comprises additional components, wherein the additional components comprise ultraviolet absorbers, pigments, fillers (calcium carbonate, titanium dioxide and the like) and combinations thereof, and the ultraviolet absorbers, the pigments and the fillers are conventional additives and can be used in conventional dosage.

The formula principle of the invention is as follows:

through the scheme, the polymer is SEBS, SBBS, SBS or SIS; SIS and SBS are preferred, and due to good thermal oxygen stability, the structure is not easy to be damaged when the reaction is carried out at high temperature; since the polyisoprene chain is broken by ozone or ultraviolet irradiation to reduce viscosity due to the unsaturated double bond, an antioxidant is added to the formulation. SIS is softer than SBS, gives the hot melt adhesive higher initial adhesion to improve the hot melt adhesive to the substrate wettability, SBS can provide higher cohesive strength, so SBS and SIS are used together.

In the invention, the preferred plasticizers such as naphthenic oil, halogen-free oligomeric phosphate ester and the like are selected to be matched with the polymer for reaction, and the compatibility with the polymer is good, so that the attraction among polymer molecular chains is weakened, the aggregation effect among the molecular chains is weakened, the mobility and the flexibility of the molecular chains are increased, the plasticity is increased, and the low-viscosity organic silicon polymer can be used for reducing the viscosity and is beneficial to a coating process. The halogen-free oligopolyphospholipid and the naphthenic oil are compounded for use, so that the flame retardant effect of the hot melt adhesive can be improved. Naphthenic oil: the dosage ratio of the halogen-free oligomeric phosphate ester is (4-6) to 1, and the optimal ratio is 5: 1.

In addition, tackifying resins such as rosin resin and maleic anhydride modified rosin ester are preferably selected, so that the adhesive property and cohesion of the hot melt adhesive are enhanced, the peel strength is improved, the chemical property of the finished hot melt adhesive is stable, and further guarantee is provided for the adhesive strength.

The flame retardant performance can be improved by selecting halogen-free phosphorus flame retardants and the like. After the inorganic flame retardant or the organic powder flame retardant is added, the inorganic flame retardant or the organic powder flame retardant is mainly dispersed and can not be completely dissolved, so that the phenomenon of sedimentation and delamination can occur when the rubber belt conveyor is placed at high temperature, and the rubber belt conveyor is blocked. The main flame retardant selected by the invention is a liquid flame retardant which is similar to a plasticizer and has good compatibility with polymers, and compared with an inorganic flame retardant or an organic powder flame retardant, the flame retardant is more suitable for spraying.

The zinc borate monomer grafted styrene resin is used to replace part of tackifying resin, and after the zinc borate monomer grafted styrene resin is added, the peeling strength is not influenced, and the flame retardant effect of the hot melt adhesive is improved.

The preparation method of the flame-retardant hot melt adhesive comprises the following steps:

s1: confirming that a bottom valve of the reaction kettle is closed, opening steam for heating, starting a stirring paddle, and adding a plasticizer with a formula amount and an antioxidant with a formula amount;

s2: raising the temperature of the reaction kettle of S1 to 135-145 ℃, adding the polymer with the formula amount, and then stirring until the polymer is completely melted; after the polymer is completely melted, adding zinc borate monomer graft polystyrene resin with the formula amount, and stirring to completely melt the zinc borate monomer graft polystyrene resin; preferably, in step S2, after the polymer is added, stirring is performed for 10-20min at a stirring speed of 50 rpm, the polymer on the tank wall of the reaction kettle and the stirring paddle is scraped by a scraper, stirring is continued at a stirring speed of 50 rpm, stirring is performed for 40-50min, whether the sample is completely melted or not is performed, if particles still exist, stirring is continued, and the extended stirring time is recorded.

S3: uniformly adding the tackifying resin with the formula amount into a reaction kettle of S2, stirring, adding the liquid flame retardant with the formula amount and the smoke suppressant with the formula amount after the tackifying resin is completely melted, and fully reacting; preferably, in step S3, after the material is added, the reaction kettle is vacuumized, the temperature in the reaction kettle is kept at 135-145 ℃, and when the vacuum degree is above 0.07 and the material is not expanded, the vacuum is pumped for 25-40 min.

S4: after the reaction in the S3 is finished, filtering the molten material in the reaction kettle;

s5: and (4) sequentially passing the molten material filtered in the step (S4) through a cooling system and a drying system, and finally packaging.

In this embodiment, the main focus of the preparation process is as follows:

(1) the raw material adding sequence is as follows: some raw materials, such as polymers, can not be melted after being added;

(2) the heating temperature is one of the key steps in the whole preparation process of the invention, because the softening point of part of raw materials such as resin is higher and the corresponding temperature requirement is needed, the temperature of the reaction kettle is kept at 135-145 ℃; if the temperature is too high, the finished product is degraded due to long production time and long-time heating and stirring, various performances are greatly reduced, and the appearance is darkened;

(3) importance of sampling in the production process: after a certain raw material is added, the raw material is ensured to be completely melted; particularly, when the polymer is added, the stirring process needs to confirm that the polymer is completely melted, because the temperature in the reaction kettle can be rapidly reduced when new raw materials are added into the reaction kettle every time, if petroleum resin is to be added, the feeding speed needs to be slowed down, the rapid reduction of the temperature in the reaction kettle is avoided, and the polymer can not be melted again in the follow-up process under the condition that the polymer is not completely melted, so that raw material particles without the melted polymer exist in a final finished product, and the performance of the finished product is seriously influenced.

The following are specific examples of the present invention, and raw materials, equipments and the like used in the following examples can be obtained by purchasing them unless otherwise specified.