CN110760184A - Polyamide material for improving paint adhesion effect and preparation method and application thereof - Google Patents

Abstract

The invention discloses a polyamide material for improving the adhesion effect of coatings, a preparation method and application thereof. Copolymer 1-6%, plasticizer 0.2-3%, lubricant 0.3-0.5%, long-term heat aging resistance 0.2-0.6% and antioxidant 0.2-0.5%. The present invention uses an ionic copolymer whose molecular side chain contains a carboxyl side group and uses a polyamide plasticizer that can inhibit the formation of hydrogen bonds between the semi-crystalline polyamide molecular chains and reduce the crystallization ability of the polyamide material. The polyamide material is modified to obtain high flow and unexpectedly good paint adhesion.

Description

A kind of polyamide material for improving paint adhesion effect, preparation method and application thereof

technical field

The invention belongs to the technical field of composite materials for automobiles, and in particular relates to a polyamide material for improving the adhesion effect of coatings and a preparation method and application thereof.

Background technique

Polyamide (nylon, PA) is an engineering plastic with excellent comprehensive properties. Nylon has high mechanical strength, heat resistance, abrasion resistance, chemical resistance and electrical insulation. Nylon materials are widely used in the automotive industry, electrical and electronic industry, transportation, machinery, aerospace and other fields. By modifying the nylon substrate with glass fiber reinforcement or mineral filling, the strength and heat resistance of nylon can be greatly improved, and the practical application value of nylon material can be given. At present, the most widely used polyamide materials in industry are semi-crystalline polyamide materials, such as PA6 and PA66.

In the automotive industry, in order to obtain the best color matching and appearance between parts in different parts, it is required that the surface of different parts or between metal and plastic or between different plastic parts have the same color or make the surface of plastic parts have metal color. The common practice is to spray the same color paint on the surface of different parts, but the paint has different adhesion to different plastic substrates. There is a strong interaction force between nylon molecular chains, and it is easy to form hydrogen bonds, so that the molecular chains are arranged neatly and have good crystalline properties. Semi-crystalline polyamide has high crystallinity, large cohesive energy, small surface tension and small surface polarity, and it is difficult for general coatings to wet the surface, resulting in poor coating adhesion.

In the prior art, the methods for improving the coating adhesion effect for plastic substrates are as follows: 1) a primer treatment is first performed on the plastic surface with a primer having good bonding force with the plastic, and the combination of the plastic and the coating is increased by the primer. 2) Oxidize the surface of the plastic substrate to increase the polarity of the surface of the plastic substrate; 3) Modify the formula of the plastic substrate, add substances containing polar functional groups to increase the polarity of the surface of the plastic substrate. Among them, primer treatment and surface oxidation treatment have more complicated procedures, high scrap rate and higher cost. Improve the polarity of the plastic substrate surface through the formulation, the steps are simple and effective.

CN 108034244 A discloses an easy-spraying mineral reinforced PA66 material and a preparation method thereof. The raw material composition of the easy-spraying mineral reinforced PA66 composite material comprises: PA6645-55 parts, PA625-35 parts, mineral filling 15-30 parts, antioxidant 0.1-0.2 parts, 3-5 parts of acid absorber, 2-3 parts of surface treatment agent. Among them, the main component to improve the surface adhesion performance of nylon is a polyvinyl alcohol surface treatment agent with a degree of polymerization of 1650-1850. However, although the polyamide material obtained by this method has good adhesion in the dry state, the surface treatment agent polyvinyl alcohol needs to be added to the composition. Loss of ingredients and increased hygroscopicity further deteriorate the dimensional stability of the polyamide material. The surface of the substrate placed in a humid environment is easy to absorb moisture, and the moisture causes the surface adhesion ability to be significantly reduced, and the coating is easy to peel off after spraying. US 20110020651 A1 discloses a polyamide material for improving spray adhesion. The main materials of the polyamide material include polyamide resin, polyol and epoxy resin, and the surface of polyamide is improved by compounding polyol and epoxy resin. paint adhesion. However, although the surface of the polyamide material obtained by this method has relatively balanced dry and wet paint adhesion, the addition of epoxy resin to the polyamide substrate will have a certain deterioration in the fluidity of the polyamide material, and the added Polypolyol will also increase the hygroscopicity of polyamide materials to a certain extent, which is not conducive to maintaining the dimensional stability of polyamide materials.

In addition, the glass-mineral fiber reinforced polyamide in the prior art is widely used in automobile interior and exterior trim parts due to its high mechanical strength, rigidity and heat resistance. For example, modified polyamide materials are used in automotive interior and exterior exterior parts, which need to match the color of plastic parts in other parts or have a metallic luster. Usually, the surface of polyamide needs to be sprayed. However, the adhesion effect of the coating on the surface of the polyamide material by using the existing common formulation technology is poor, and the glass-mineral fiber modified polyamide material obtained by the prior art has poor fluidity and poor dry and wet adhesion of the coating.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the prior art and provide a polyamide material that improves the adhesion effect of paint.

Another object of the present invention is to provide a preparation method of the above-mentioned polyamide material.

Another object of the present invention is to provide the application of the above-mentioned polyamide material.

The technical scheme of the present invention is as follows:

A polyamide material for improving the adhesion effect of paint is made of the following components by weight percentage:

The relative viscosity R.V. of the above-mentioned semi-crystalline polyamide is 2.4-2.8;

The above-mentioned glass mineral fibers are at least one of glass fibers with a diameter of 7-20 μm and a length of 0.1-5 mm, acicular wollastonite and calcium sulfate whiskers;

Above-mentioned ionic copolymer contains carboxyl side group or maleic anhydride side group, and this carboxyl side group or maleic anhydride side group is neutralized by alkali metal ion to form ionic bond cross-linking;

The above-mentioned plasticizer is a compound capable of suppressing the formation of hydrogen bonds between the molecular chains of the semi-crystalline polyamide to reduce the crystallinity.

In a preferred embodiment of the present invention, it is made of the following components by weight:

Further preferably, the semi-crystalline polyamide is at least one of PA6, PA66, PA11, PA12, PA46, PA56, PA610, PA612 and PA1010.

Still further preferably, the semi-crystalline polyamide is PA6 or PA66.

Further preferably, the glass mineral fiber is acicular wollastonite with a diameter of 12 μm and a length of 156 μm.

Further preferably, the ionic copolymer is a copolymer formed by repeating units of ethylene, α, β-unsaturated C3-C8 carboxylic acid derivatives or/and unsaturated dicarboxylic acid derivative comonomers. The carboxyl pendant groups are partially neutralized by alkali metal ions to form ionic crosslinks.

Still further preferably, the ionic copolymer is an ethylene-isobutyl acrylate-methacrylic acid-zinc ion ternary ionic copolymer.

9020离子共聚物。More preferably, the ionic copolymer is

9020 ionic copolymer.

Further preferably, the plasticizer is N-butylbenzenesulfonamide.

Further preferably, the lubricant is at least one of stearate, ethylene acrylic acid copolymer and amide lubricant, the long-term heat aging resistance agent is a copper salt heat stabilizer, and the antioxidant is At least one of 1098, 168, 9228, 1010 and H161.

Still further preferably, the lubricant is ethylene acrylic acid copolymer AC-540A, and the long-term heat aging resistance agent is H3386.

Another technical scheme of the present invention is as follows:

The preparation method of above-mentioned polyamide material, comprises the steps:

(1) each component is weighed by described weight percentage;

(2) uniformly mixing the semi-crystalline polyamide, ionic copolymer, plasticizer, lubricant, long-term heat-aging agent and antioxidant to obtain the main ingredient;

(3) The above-mentioned main material is metered and fed from the main feeding port of the twin-screw extruder through loss-in-weight weighing, and the glass fiber is metered and fed through the loss-in-weight weighing from the side feeding port of the twin-screw extruder. The polyamide material is obtained after melt extrusion, water cooling and pelletizing in a twin-screw extruder.

Another technical scheme of the present invention is as follows:

The application of the above-mentioned polyamide material as the raw material of the polyamide component for spraying the interior and exterior decoration of automobiles.

The beneficial effects of the present invention are:

1. In the present invention, a specific plasticizer that can inhibit the formation of hydrogen bonds between the semi-crystalline polyamide molecular chains and reduce the crystallization ability of the polyamide material is added to the polyamide, so that the polyamide molecular chain can not be broken. The mechanical properties of the reinforced polyamide material are fully maintained. At the same time, due to the inhibition of the formation of hydrogen bonds between some polyamide molecular chains, the crystallinity and cohesive energy of the polyamide are also reduced, which greatly improves the lubrication of the coating to the semi-crystalline polyamide. Wetting and penetration capacity.

2. The ionic copolymer with carboxyl side groups added in the present invention can greatly improve the surface polarity of the polyamide material while fully maintaining the fluidity of the polyamide material, and improve the surface energy of the polyamide material, which is beneficial to epoxy or acrylic Wetting of the coating, that is to say, the polyamide material provided by the present invention to improve the coating adhesion effect can simultaneously obtain the high fluidity of the modified polyamide material and the high dry and wet adhesion effect of the coating, and can be used as a spray polyamide for interior and exterior decoration of automobiles. Component preparation raw material application.

Detailed ways

The technical solutions of the present invention will be further illustrated and described below through specific embodiments.

8)。离子聚合物为9020(购自Dupont公司)。增塑剂为市购N-丁基苯磺酰胺(购自百灵威科技有限公司，纯度为99％)。润滑剂为AC-540A(购自霍尼韦尔Honeywell公司)。耐长期热老化剂为H3386(购自布吕格曼公司)。抗氧剂为1098(购自天津利安隆新材料股份有限公司)。聚乙烯醇为日本可乐丽公司POVAL28～98(粘度25.0～31.0cps，醇解度＝98.0～99.0％)。环氧树脂为国都化工牌号YD-012A80(环氧当量值为600～700g/eq)。双螺杆挤出机为具有主喂料口和侧喂料口的双螺杆挤出机，具体为长径比为40∶1的瑞亚RXT-65，其包括十一区，主喂料口位于一区，侧喂料口位于五区。In the following examples and comparative examples: the semi-crystalline polyamide is PA66 with a relative viscosity RV of 2.4, such as EPR24 (purchased from Shenma Industrial Co., Ltd.). Acicular wollastonite with a glass fiber diameter of 12 μm and a length of 156 μm (purchased from the U.S. NYCO company

8). Ionic polymers are 9020 (purchased from Dupont). The plasticizer was commercially available N-butylbenzenesulfonamide (purchased from Bailingwei Technology Co., Ltd., with a purity of 99%). The lubricant was AC-540A (available from Honeywell). The long-term heat-aging agent is H3386 (purchased from Brueggermann). The antioxidant was 1098 (purchased from Tianjin Li'anlong New Materials Co., Ltd.). The polyvinyl alcohol is POVAL28-98 of Japan Kuraray Company (viscosity 25.0-31.0cps, alcoholysis degree=98.0-99.0%). The epoxy resin is Guodu Chemical's grade YD-012A80 (epoxy equivalent value is 600-700g/eq). The twin-screw extruder is a twin-screw extruder with a main feeding port and a side feeding port, specifically Rhea RXT-65 with an aspect ratio of 40:1, which includes eleven zones, and the main feeding port is located at One zone, the side feeding port is located in the fifth zone.

Examples 1 to 3

(1) Put the semi-crystalline polyamide, ionic polymer, plasticizer, lubricant, long-term heat aging resistance agent and antioxidant into a low-speed mixer, mix at a speed of 100r/min for 5 minutes, and mix thoroughly to form the main material ,spare;

(2) The above-mentioned main materials are metered and fed from the main feeding port of the twin-screw extruder through loss-in-weight weighing, and the chopped glass fibers are separately metered and fed from the side feeding port of the twin-screw extruder through loss-in-weight weighing; The temperatures of each section of the screw extruder are: 230°C, 265°C, 270°C, 270°C, 265°C, 255°C, 255°C, 245°C, 245°C, 245°C, the head temperature is 270°C, and the screw speed It is 400r/min; the material is fully fused under the shearing, kneading and conveying of the screw, and finally it is extruded, drawn, cooled by water, and pelletized to make polyamide material pellets that improve the adhesion effect of the coating. The dosage of each component is shown in Table 1.

Comparative Example 1

The polyamide material pellets for improving the coating adhesion effect were prepared according to the method of Example 1. The difference was that the ionic polymer and the plasticizer were replaced by PA66 resin in the same weight portion, and the remaining conditions were the same as those in Example 1, and the reference Polyamide material pellets for improved paint adhesion. The dosage of each component is shown in Table 1.

Comparative Example 2

The polyamide material pellets for improving the coating adhesion effect were prepared according to the method of Example 2, except that the plasticizer was replaced by the same weight portion of polyvinyl alcohol POVAL 28-98 and the ionic polymer was replaced by the same weight portion of PA66 The resin was replaced, and the remaining conditions were the same as those in Example 2, to obtain the reference polyamide material pellets which improved the coating adhesion effect. The dosage of each component is shown in Table 1.

Comparative Example 3

The polyamide material pellets for improving the coating adhesion effect were prepared according to the method of Example 2, except that the plasticizer was replaced by epoxy resin YD-012A80 of the same weight part and the ion polymer was replaced by the PA66 resin of the same weight part Instead, the remaining conditions are the same as in Example 2, to obtain the reference polyamide material pellets with improved coating adhesion effect. The dosage of each component is shown in Table 1.

The specific steps of Comparative Examples 1 to 3 are as follows:

(1) Put semi-crystalline polyamide, polyvinyl alcohol or epoxy resin, lubricant, long-term heat aging resistance agent and antioxidant into a low-speed mixer, mix at a speed of 100r/min for 5 minutes, and mix thoroughly to form the main material ,spare;

(2) The above-mentioned main materials are metered and fed from the main feeding port of the twin-screw extruder through loss-in-weight weighing, and the chopped glass fibers are separately metered and fed from the side feeding port of the twin-screw extruder through loss-in-weight weighing; The temperatures of each section of the screw extruder are: 230°C, 265°C, 270°C, 270°C, 265°C, 255°C, 255°C, 245°C, 245°C, 245°C, the head temperature is 270°C, and the screw speed It is 400r/min; the material is fully fused under the shearing, kneading and conveying of the screw, and finally it is extruded, drawn, cooled by water, and pelletized to make polyamide material pellets that improve the adhesion effect of the coating. The dosage of each component is shown in Table 1.

test case

The polyamide material pellets obtained from Examples 1 to 3 for improving the coating adhesion effect and the polyamide material pellets for improving the coating adhesion effect obtained from Comparative Examples 1 to 3 were placed in a blast dryer at 90 ° C for drying for 4 hours , and then inject the dried particles at a temperature of 265-285° C. to obtain test specimens.

Table 1 The dosage of each component (wt%)

Table 2

Remarks: 1* In Table 2, + is the good degree, the more + the better; - is the bad degree, the more - the bad.

2*Dry adhesion test: evenly spray the commercially available acrylic paint to 60mm*60mm*2mm under the same conditions, after drying in an oven at 60°C for 4 hours, use a blade or a crossbar to mark on the sprayed coating 1mm*1mm at least 36 grids, use Japan or the United States 3M strong tape to stick and test 6 times, the less the grids fall off, the stronger the adhesion.

3* Adhesion test of soaking in water: under the same conditions, spray the commercially available acrylic paint to 60mm*60mm*2mm evenly, bake in an oven at 60°C for 4 hours, soak the sample in water at 23°C for 48 hours, and then use a blade or a crossbar. Draw at least 36 grids of 1mm*1mm on the sprayed coating, and repeat the inspection 6 times with 3M strong tape from Japan or the United States. The fewer grids fall off, the stronger the adhesion.

It can be seen from the data in Table 2 that samples of the same thickness were prepared under the same injection molding process in Examples 1-3 and Comparative Examples 1-3. High toughness and high melt index are obtained, and the surface finish of injection molded samples is high. The modified polyamide material obtained in Comparative Example 1 has poor fluidity, surface finish and dry and wet adhesion of the coating. In Comparative Example 2, after adding polyvinyl alcohol to PA66, the dry adhesion effect of the coating is good, but the wet adhesion effect is poor. In Comparative Example 3, after adding epoxy resin to PA66, the dry and wet adhesion effect of the coating is good, but after adding epoxy resin, the fluidity of polyamide material is seriously deteriorated, and the appearance effect of injection molding product is seriously deteriorated. In conclusion, the ionic polymer and plasticizer added in Examples 1 to 3 can achieve both high fluidity of the modified polyamide material and high dry and wet adhesion of the coating.

The above are only the preferred embodiments of the present invention, so the scope of implementation of the present invention cannot be limited accordingly, that is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the description should still be covered by the present invention. In the range.

Claims (10)

1. A polyamide material for improving the adhesion effect of a coating is characterized in that: the composition is prepared from the following components in percentage by weight:

the relative viscosity R.V. of the semi-crystalline polyamide is 2.4-2.8;

the glass mineral fiber is at least one of glass fiber with the diameter of 7-20 mu m and the length of 0.1-5mm, needle-shaped wollastonite and calcium sulfate whisker;

the ionic copolymer contains carboxyl side groups or maleic anhydride side groups, and the carboxyl side groups or the maleic anhydride side groups are neutralized by alkali metal ions to form ionic bonds for crosslinking;

the plasticizer is a compound capable of suppressing hydrogen bonds formed between molecular chains of the semicrystalline polyamide to reduce the crystallization ability.

2. The polyamide material of claim 1, wherein: the composition is prepared from the following components in percentage by weight:

3. polyamide material according to claim 1 or 2, characterized in that: the semi-crystalline polyamide is at least one of PA6, PA66, PA11, PA12, PA46, PA56, PA610, PA612 and PA 1010.

4. Polyamide material according to claim 1 or 2, characterized in that: the glass mineral fiber is needle-shaped wollastonite with the diameter of 12 mu m and the length of 156 mu m.

5. The polyamide material of claim 1, wherein the ionic copolymer is a copolymer of ethylene, a derivative of α -unsaturated C3-C8 carboxylic acid and/or a comonomer of an unsaturated dicarboxylic acid derivative, wherein the pendant carboxyl groups of the copolymer are partially neutralized with alkali metal ions to form ionic crosslinks.

6. The polyamide material of claim 5, wherein: the ionic copolymer is an ethylene-isobutyl acrylate-methacrylic acid-zinc ion ternary ionic copolymer.

7. Polyamide material according to claim 1 or 2, characterized in that: the plasticizer is N-butyl benzene sulfonamide.

8. Polyamide material according to claim 1 or 2, characterized in that: the lubricant is at least one of stearate, ethylene acrylic acid copolymer and amide lubricant, the long-term heat aging resistant agent is a copper salt heat stabilizer, and the antioxidant is at least one of 1098, 168, 9228, 1010 and H161.

9. Process for the preparation of a polyamide material according to any one of claims 1 to 8, characterized in that: the method comprises the following steps:

(1) weighing the components according to the weight percentage;

(2) uniformly mixing the semi-crystalline polyamide, the ionic copolymer, the plasticizer, the lubricant, the long-term heat aging resistant agent and the antioxidant to obtain a main material;

(3) and (2) feeding the main materials from a main feeding port of a double-screw extruder in a weight-loss scale metering manner, feeding the glass mineral fibers from a side feeding port of the double-screw extruder in a weight-loss scale metering manner, and performing melt extrusion, water cooling and grain cutting in the double-screw extruder to obtain the polyamide material.

10. Use of a polyamide material according to any one of claims 1 to 8 as a starting material for spray-applied polyamide-based components for automotive interiors and exteriors.