CN114656785A - A kind of high weld line strength polyamide composite material and its preparation method and application - Google Patents

Abstract

A high weld line strength polyamide composite material, comprising the following components in parts by weight: 60 parts of semi-aromatic polyamide resin; 10-30 parts of flame retardant; 0-60 parts of reinforcing material; 0.01 part of triamine compound ‑1 serving. In the present invention, a certain amount of triamine compounds are added to react with the terminal carboxyl groups of the semi-aromatic polyamide resin to form a micro-crosslinking system, so that the welding line of the polyamide composite material can be wound more effectively, so as to improve the strength of the welding line. purpose, but also improve the blister resistance, especially suitable for SMT assembly process.

Description

A kind of high weld line strength polyamide composite material and its preparation method and application

technical field

The invention relates to the technical field of polymer materials, in particular to a high solvent strength polyamide composite material and a preparation method and application thereof.

Background technique

In recent years, with the high density of electronic products and the miniaturization of products, lead-free surface mount technology (SMT) has become an important way of assembly. Its application requires components that can withstand high temperatures of 250-280 °C. Traditional engineering plastics such as PA66 and PBT cannot meet this requirement at all, and high temperature engineering plastics emerge as the times require. Semi-aromatic polyamide (PPA) is widely used in the field of connectors due to its high melting point, high heat distortion temperature and high strength.

Connector products must have high fluidity, rapid prototyping, and high weld line strength characteristics due to the multi-PIN pin structure; different from traditional connectors, SMT assembly method requires materials to pass 250-280 ℃, this process is equivalent to When the thin-walled material undergoes rapid aging, the properties of the material will decline in all aspects, especially the weld line strength of the product, which will decline significantly.

Generally speaking, the common methods for improving material weld lines in the prior art are:

First, improve the product structure or mold structure, improve the convergence angle of the product weld line, or design the weld line in a non-stressed position, such as the application number 202022094118 (the mold structure for solving the product surface weld line). However, this puts forward high requirements on product structure and mold structure design, and is not versatile, and also increases the cost of design and products.

Second, from the formula design, improve the weld line strength of the material. For example, patent application 200810218925 discloses a high weld line strength reinforced polypropylene material and a preparation method thereof. The combination of reinforcing material and resin is improved by adding a coupling agent, thereby improving the weld line strength of the material; patent application 201510900503 discloses a high weld line strength. Polyamide material with weld line strength, preparation method and application thereof, which reduce the crystallinity behavior of the material and improve the fluidity of the material by adding a low-viscosity amorphous polyamide compound. The above two solutions can indeed improve the weld line strength of the material, but they are not suitable for SMT products injected with high temperature nylon. The reason is: the current commercially available coupling agents are mainly liquid silane coupling agents, which are easy to volatilize and are difficult to apply to high-temperature nylon processing. It is also easy to cause the material to contain a large amount of small molecular residues, resulting in foaming during reflow soldering. Low-viscosity amorphous compounds will destroy the crystalline behavior of the compound, reduce the cooling rate of the material, and are prone to abnormalities such as burrs when injecting thin-walled products.

At the same time, due to the introduction of halogen-free flame retardants in the flame-retardant polyamide system, the material will generate more gas during extrusion and processing, making the injection-molded products more likely to cause damage in the SMT assembly method. Foaming, which affects product functionality and appearance.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a high weld line strength polyamide composite material with improved foaming resistance.

Another object of the present invention is to provide a method for preparing the above-mentioned high weld line strength polyamide composite material.

The present invention is achieved through the following technical solutions:

A high weld line strength polyamide composite material, in parts by weight, comprising the following components:

60 parts of semi-aromatic polyamide resin;

Flame retardant 10-30 copies;

Reinforcing material 0-60 copies;

0.01-1 part of triamine compound.

Described semi-aromatic polyamide resin is derived from diacid unit and diamine unit; Described diacid unit is derived from 45-100mol% of aromatic dicarboxylic acid and 0-55mol% of aliphatic dicarboxylic acid, so Described aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, 2-methyl terephthalic acid, 2,5-dichloroterephthalic acid, 2,6-naphthalene dicarboxylic acid, 1,4- At least one of naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, and 2,2'-biphenyl dicarboxylic acid, the number of carbon atoms of the aliphatic dicarboxylic acid is 4-12; Amine units derived from 1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine Carbodiamine, 1,12-dodecanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,4-dimethyl-1, 6-Hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8 -At least one of octanediamine and 5-methyl-1,9-nonanediamine.

The aliphatic dicarboxylic acid is selected from 1,4-succinic acid, 1,6-adipic acid, 1,8-suberic acid, 1,9-azelaic acid, 1,10-sebacic acid, At least one of 1,11-undecanedioic acid and 1,12-dodecanedioic acid.

The semi-aromatic polyamide resin used in the embodiment of the present invention is a self-made raw material, and the method is as follows:

The metered materials were added to a 20 L autoclave, and 2‰ (total substance mass) of 1098 antioxidant and 1‰ (total substance mass) of sodium hypophosphite catalyst were fixedly added. In the preparation of semi-aromatic polyamide resin, benzoic acid was used as the end-capping agent, and the dosage was 0.02 times the molar amount of aromatic dicarboxylic acid units, and the amine-carboxyl ratio (molar ratio) was 0.995. It reacts with triamine compounds in the process. After the feeding is completed, after vacuuming and nitrogen filling to replace the gas, it is heated to a predetermined temperature of 230-240° C., and a constant pressure of 2.9-3.1 MPa is maintained by removing the formed water. After the reaction was completed, the pressure was released to normal pressure to obtain a prepolymer. The prepolymer is solid-phase tackified at 240-250° C. in a rotating drum, and the semi-aromatic polyamide resin can be obtained after tackifying for 1-3 hours.

The flame retardant is selected from at least one of phosphinate flame retardants or dialkyl phosphinate flame retardants.

The reinforcing material is selected from glass fiber, carbon fiber, asbestos fiber, wollastonite fiber, ceramic fiber, potassium titanate whisker, basic magnesium sulfate whisker, silicon carbide whisker, aluminum borate whisker, silicon dioxide, At least one of aluminum silicate, silica, calcium carbonate, titanium dioxide, talc, wollastonite, diatomaceous earth, clay, kaolin, spherical glass, mica, and gypsum.

The structure of the triamine compound is as follows, wherein R ₁ , R ₂ , R ₃ are hydrogen, or an alkyl chain compound with 1-12 carbon atoms containing a terminal amine group,

。

.

Specifically, in Structural Formula 1, n ₁ =any integer of 1-12, m ₁ =any integer of 1-12, and n ₁ and m ₁ may be the same or different values; in Structural Formula 2, n ₂ =1-12 Any integer of , m ₂ = any integer of 1-12, L = any integer of 1-12, n ₂ , m ₂ , L can be the same or different values;

。

.

Preferably, the structure of the triamine compound is structural formula 1.

Preferably, the content of the triamine compound is 0.20-0.75 parts by weight.

0-2 parts of auxiliary agents can be optionally added according to actual needs, and the auxiliary agents are selected from at least one of lubricants and oxidants.

The preparation method of the high weld line strength polyamide composite material of the present invention includes the following method: according to the proportion, the components other than the reinforcing material are mixed uniformly, and then extruded and granulated through a twin-screw extruder, and at 250- After melt blending at 350° C., cooling and pelletizing to obtain a polyamide composite material with high weld line strength.

The application of the high weld line strength polyamide composite material of the present invention is used in SMT manufacturing processes, such as lamp strip brackets, LED reflection brackets, and also in high-voltage connector products, low-voltage electrical products, relays, 5G communication connectors and other fields.

The present invention has the following beneficial effects:

In the present invention, a certain amount of triamine compounds are added to react with the terminal carboxyl groups of the semi-aromatic polyamide resin to form a micro-crosslinking system, so that the welding line of the polyamide composite material can be wound more effectively, so as to improve the strength of the welding line. purpose, but also improve the blister resistance, especially suitable for SMT assembly process.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

The sources of raw materials used in Examples and Comparative Examples are as follows:

PA10T, self-made;

PA5T/56, terephthalic acid accounts for 70mol% of total acid, self-made;

PA6T/66, terephthalic acid accounts for 60mol% of total acid, self-made;

PA10T/1010, terephthalic acid accounts for 85mol% of total acid, self-made;

PA10T/10I, terephthalic acid accounted for 90mol% of total acid, self-made.

Flame Retardant A: Aluminum Diethylphosphinate, OP1230, Clariant;

Flame Retardant B: Zinc Diethylphosphinate, PFR1210, Changzhou Hongyu Chemical Co., Ltd.;

Glass fiber: commercially available, the same kind of glass fiber was used in parallel tests;

Triamine compound A-1: structural formula 1 (n ₁ =6, m ₁ =6), bis(hexamethylene)triamine, Shanghai Aladdin Biochemical Technology Co., Ltd.;

Triamine compound A-2: structural formula 1 (n ₁ =9, m ₁ =9), according to the document "Synthesis and Biological Evaluation of Bivalent Ligands for the Cannabinoid 1 Receptor" ( J. Med.Chem. 2010, 53, 7048– 7060 DOI: 10.1021/jm1006676) method;

Triamine compound A-3: structural formula 1 (n ₂ =11, m ₂ =11), according to "Synthesis and Biological Evaluation of Bivalent Ligands for the Cannabinoid 1 Receptor" (J. Med.Chem. 2010, 53, 7048– 7060 DOI: 10.1021/jm1006676) method;

Triamine compound B-1: structural formula 2 (n ₃ =5, m ₃ =5, L=5), prepared according to the international patent of "A method for preparing alkylated amines", international patent number WO 2021/174523 Al, method;

Triamine compound B-2: structural formula 2 (n ₃ =7, m ₃ =7, L=7), prepared according to the international patent "A method for preparing alkylated amines", international patent number WO 2021/174523 Al, method;

Lubricant: Commercially available, the same lubricant was used in parallel experiments.

The preparation method of the polyamide composite material of Examples and Comparative Examples: according to the proportion, the components other than the reinforcing material are mixed uniformly, and then extruded and granulated through a twin-screw extruder, and the reinforcing material is side-fed at 250-350 After melt blending at ℃, cooling and pelletizing to obtain a polyamide composite material with high weld line strength.

Various test methods:

(1) Tensile strength: The polyamide composition is glued from one side and injected into ISO tensile test strips; the test strips are adjusted in a laboratory standard environment of 23 ° C and 50% RH for 24 hours according to ISO-527- 2:2012 Standard Test Tensile Strength.

(2) Weld line strength before reflow soldering: The polyamide composition was injected into the glue from both sides at the same time, and injection molded into ISO tensile test specimens. The fusion line meeting position was in the middle of the tensile test specimens; The weld line strength was tested according to the ISO-527-2:2012 standard after conditioning in a 50% RH laboratory standard environment for 24 hours.

(3) Weld line strength after reflow soldering: The polyamide composition was injected into the glue from both sides at the same time, and injection molded into ISO tensile test specimens, and the fusion line meeting position was in the middle of the tensile test specimens; In the SER-710A equipment of East Technology (Shenzhen) Co., Ltd., the temperature rises from room temperature to 150°C in 45 seconds in air, and from 150°C to 200°C in 135 seconds, with a maximum temperature rise rate of 3°C The temperature rises to 260°C/s, and the time above 255°C is 20-40s, and then cools down to room temperature at a maximum temperature drop rate of 6°C/s; finally, the test specimens are placed in a laboratory standard environment of 23°C and 50% RH. After conditioning for 24 hours, the weld line strength was tested according to the ISO-527-2:2012 standard.

(4) Foaming resistance temperature: The polyamide composite materials of the examples or comparative examples were dried at 120°C for 4 hours, then injected into a 60*60*1mm square plate, and tested after being soaked in water at 23°C for 24 hours. The test piece was placed in the SER-710A equipment of Ziguang Ridong Technology (Shenzhen) Co., Ltd., and the temperature was raised from room temperature to 150 °C in 45 seconds in the air, and from 150 °C to 200 °C in 135 seconds. The maximum temperature rise rate is 3 °C/s to the peak temperature °C, and then the maximum temperature drop rate is 6 °C/s to cool down to room temperature, take out the test piece and observe whether there is foaming; the peak temperature is 250 °C as the starting point , and gradually increase with 5 °C as a step. When the test piece foams, the corresponding peak temperature -5 °C is the foaming resistance temperature.

Table 1: Contents (parts by weight) and test results of each component of the high weld line polyamide composite material of Examples 1-6

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PA10T 60 60 60 60 60 60 Flame Retardant A 20 20 20 20 20 20 glass fiber 30 30 30 30 30 30 Triamine compound A-1 0.3 0.3 Triamine compound A-2 0.3 Triamine compound A-3 0.3 Triamine compound B-1 0.3 Triamine compound B-2 0.3 lubricant 0.2 Tensile strength, MPa 140 138 137 135 132 140 Weld line strength before reflow soldering, MPa 57 54 53 52 50 58 Weld line strength after reflow soldering, MPa 54 50 47 47 45 54 Foaming resistance temperature, °C 275 275 275 275 275 270

It can be seen from Examples 1-5 that the triamine compound of structural formula 1 is preferred, and the weld line strength is better.

It can be seen from Example 1/6 that the addition of lubricant can improve the weld line strength to a certain extent, but also affects the foaming resistance temperature.

Table 2: Contents (parts by weight) and test results of each component of the high weld line polyamide composite material in Examples 7-13

Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 PA10T 60 60 60 PA5T/56 60 PA6T/66 60 PA10T/1010 60 PA10T/10I 60 Flame Retardant A 10 20 20 20 20 20 Flame Retardant B 30 glass fiber 10 40 60 30 30 30 30 Triamine compound A-1 0.01 0.6 1.0 0.3 0.3 0.3 0.3 Tensile strength, MPa 100 145 170 150 148 142 140 Weld line strength before reflow soldering, MPa 54 53 57 55 54 50 48 Weld line strength after reflow soldering, MPa 51 48 53 49 48 45 44 Foaming resistance temperature, °C 270 270 280 260 260 275 275

It can be seen from Examples 7-13 and Comparative Examples that the objects of the present invention can be achieved within the scope of the present invention.

Table 3: Contents (parts by weight) and test results of each component of the high weld line polyamide composite material in Examples 14-17

Example 14 Example 15 Example 16 Example 17 PA10T 60 60 60 60 Flame Retardant A 20 20 20 20 glass fiber 30 30 30 30 Triamine compound A-1 0.01 0.2 0.75 1.0 Tensile strength, MPa 140 140 140 138 Weld line strength before reflow soldering, MPa 55 56 53 51 Weld line strength after reflow soldering, MPa 48 51 50 48 Foaming resistance temperature, °C 270 275 280 280

It can be seen from Examples 1/14-17 that the overall performance is better when the content of the triamine compound is preferably 0.20-0.75 parts by weight.

Table 4: Contents (parts by weight) and test results of each component of the high weld line polyamide composite material of the comparative example

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 PA10T 60 60 PA6T/66 60 PA5T/56 60 Flame Retardant A 20 20 20 20 glass fiber 30 30 30 30 Triamine compound A-1 1.2 Tensile strength, MPa 138 140 145 142 Weld line strength before reflow soldering, MPa 45 53 51 48 Weld line strength after reflow soldering, MPa 42 40 38 36 Foaming resistance temperature, °C 280 265 250 250

It can be seen from Comparative Example 1 that if the amount of triamine compound added is too high, the strength of the weld line will be reduced instead.

It can be seen from Comparative Examples 2-4 that when no triamine compound is added, the weld line strength after reflow soldering is very low, and the blister resistance temperature is also low.

Claims (10)

1. a high weld line strength polyamide composite material, is characterized in that, by weight, comprises the following components: 60 parts of semi-aromatic polyamide resin; Flame retardant 10-30 copies; Reinforcing material 0-60 copies; 0.01-1 part of triamine compound. 2. The high weld line strength polyamide composite material according to claim 1, wherein the semi-aromatic polyamide resin is derived from a diacid unit and a diamine unit; the diacid unit is derived from 45 -100mol% aromatic dicarboxylic acid and 0-55mol% aliphatic dicarboxylic acid, the aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, 2-methyl terephthalic acid, 2 At least one of ,5-dichloroterephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid and 2,2'-biphenyl dicarboxylic acid , the number of carbon atoms of the aliphatic dicarboxylic acid is 4-12; the diamine unit is derived from 1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2-methyl-1,5-pentanediamine, 3 -Methyl-1,5-pentanediamine, 2,4-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4, At least one of 4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine. 3. The high weld line strength polyamide composite material according to claim 2, wherein the aliphatic dicarboxylic acid is selected from the group consisting of 1,4-succinic acid, 1,6-adipic acid, 1,4- At least one of 8-octanedioic acid, 1,9- azelaic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid and 1,12-dodecanedioic acid. 4. The high weld line strength polyamide composite material according to claim 1, wherein the flame retardant is selected from the group consisting of phosphinate flame retardants or dialkyl phosphinate flame retardants. at least one. 5. The high weld line strength polyamide composite material according to claim 1, wherein the reinforcing material is selected from the group consisting of glass fiber, carbon fiber, asbestos fiber, wollastonite fiber, ceramic fiber, potassium titanate whisker , Basic magnesium sulfate whiskers, silicon carbide whiskers, aluminum borate whiskers, silicon dioxide, aluminum silicate, calcium carbonate, titanium dioxide, talc, wollastonite, diatomaceous earth, clay, kaolin, spherical glass, mica, at least one of gypsum. 6 . The high weld line strength polyamide composite material according to claim 1 , wherein the structure of the triamine compound is as follows, wherein R ₁ , R ₂ , and R ₃ are hydrogen, or the number of carbon atoms is 1-12 alkyl chains containing terminal amino groups, or aromatic ring compounds containing terminal amino groups,

; Described triamine compound is selected from at least one in following structural formula; Wherein, in structural formula 1, n ₁ =any integer of 1-12, m ₁ =any integer of 1-12; in structural formula 2, n ₂ =any integer of 1-12, m ₂ =any integer of 1-12, L= Any integer from 1-12;

. 7 . The high weld line strength polyamide composite material according to claim 1 , wherein the content of the triamine compound is 0.20-0.75 parts by weight. 8 . 8 . The high weld line strength polyamide composite material according to claim 1 , wherein the triamine compound is selected from structural formula 1. 9 . 9. The preparation method of the high weld line strength polyamide composite material according to any one of claims 1-8, characterized in that it comprises the following method: according to the ratio, the components other than the reinforcing material are uniformly mixed, and then the Extrusion and granulation through a twin-screw extruder, after melt blending at 250-350° C., cooling and granulation to obtain a polyamide composite material with high weld line strength. 10. The application of the high weld line strength polyamide composite material according to any one of claims 1-8, characterized in that it is used in an SMT manufacturing process.