WO2017092067A1 - Low-warpage and high-hardness polymer and preparation method therefor - Google Patents

Abstract

A low-warpage and high-hardness polymer, consisting of the following components calculated in weight percentages: 40-80% of a POK resin, 0.1-2% of a compatibilizer, 0.1-5% of a processing aid and 20-60% of glass fibres. Compared with conventional engineering plastics, the polymer obtained through the steps of material preparing, mixing and extruding has a more excellent impact resistance and chemical resistance, and a higher hardness and abrasion resistance; the hardness and the abrasion resistance are far higher than those of the current hardest polymer POM (polyformaldehyde); and the warpage is low, thus making the low-warpage and high-hardness polymer suitable for occasions where the precision requirement is high.

Description

Low warpage high hardness polymer and preparation method thereof Technical field

The invention belongs to the field of polymer materials, and particularly relates to a low warpage and high hardness polymer and a preparation method thereof.

Background technique

In 2008, with Apple as the representative, consumer electronics began to be ultra-thin. Subsequently, the touch smart phone, the Pad and the last Intel Ultrabook were all continuing the design concept of light weight and ultra-thin. Apple has emerged as the leading brand of consumer electronics, pursuing a paranoid pursuit of consumer experience and product design excellence. Apple has widely used new magnesium alloy materials to achieve lightweight and ultra-thin design.

However, magnesium alloys are expensive in terms of unit price, have many production processes, and have low processing efficiency. Designers face the problem: 1) cost control of thin and light design. To meet the user's thin and light mobile experience, reduce costs, improve cost performance is the key to sales; 2) OEM plant capacity limit. The integrated CNC equipment for magnesium alloy molding is mostly the capital investment of the earliest Apple project. Mac and iPad occupy most of the production capacity, and the new capital investment will increase the amortization cost of the OEM.

Therefore, the low cost, high manufacturing efficiency alternatives for magnesium alloys have become the goal of many material suppliers. Engineering plastics are the first choice for their low cost, small specific gravity and high processing efficiency. In addition to having a high modulus, good dimensional stability and high hardness are also one of the key factors.

Summary of the invention

In order to solve the above problems, the invention discloses a low warpage and high hardness polymer and a preparation method thereof, the preparation process is simple, the mechanical properties are excellent, and the material molding liquidity is good. It has high modulus, low warpage and high hardness, good appearance, and convenient processing. It has a wide processing window and can meet the precision requirements of electronic products.

In order to achieve the above object, the technical solution of the present invention is as follows:

A low warpage and high hardness polymer consisting of the following components by weight:

As a modification of the present invention, the POK resin includes known POKs of all viscosities.

As a modification of the present invention, the compatibilizing agent is a polymer containing a maleic anhydride graft.

As an improvement of the present invention, the processing aid is an antioxidant, and the antioxidant is 168 or 1010.

As a modification of the present invention, the glass fiber has a circular or rectangular cross section; wherein the rectangular cross section is a region in which the glass fiber has a non-circular cross section, and the size of the main cross section axis and the secondary cross sectional axis The ratio is 2-6, preferably 3-5.

The preparation method of the low warpage high hardness polymer of the invention comprises the following steps:

(1) Preparation of raw materials: consisting of the following components in terms of weight percent:

(2) mixing: mixing POK resin, compatibilizer and processing aid in a high mixer for 20-30 min;

(3) Extrusion: the mixture after step (2) is fed into the screw extruder from the main feed port, the glass fiber is fed into the screw extruder from the side, and the flame retardant is added to the screw extruder from the lateral or main feed port. The screw speed is 350-600 rpm; the temperature from the head to the feeding port is 120-230 ° C in one zone, 170-240 ° C in the second zone, and the temperature in the three to seven zones is adjusted at 170-240 ° C, and the temperature of the feeding port is 170-240 ° C.

The beneficial effects of the invention are:

The invention discloses a low warpage and high hardness polymer, which has scientific selection and strict preparation method, and the obtained polymer has more excellent impact resistance, chemical resistance and higher performance than conventional engineering plastics. Hardness and wear resistance, hardness and wear resistance are much higher than the current hardest polymer POM polyoxymethylene, and the warpage is low, which is suitable for occasions with high precision requirements.

detailed description

The invention is further clarified by the following detailed description of the invention, which is to be construed as illustrative only.

The preparation method of the low warpage high hardness polymer of the invention comprises the following steps:

(1) Preparation of raw materials: consisting of the following components in terms of weight percent:

(2) mixing: mixing POK resin, compatibilizer and processing aid in a high mixer for 20-30 min;

(3) Extrusion: the mixture after step (2) is fed into the screw extruder from the main feed port, the glass fiber is fed into the screw extruder from the side, and the flame retardant is added to the screw extruder from the lateral or main feed port. The screw speed is 350-600 rpm; the temperature from the head to the feeding port is 120-230 ° C in one zone, 170-240 ° C in the second zone, and the temperature in the three to seven zones is adjusted at 170-240 ° C, and the temperature of the feeding port is 170-240 ° C.

According to the above preparation method, the raw materials used in the examples are shown in Table 1:

The formula table of the embodiment is shown in Table 2:

The preparation parameters are shown in Table 3:

parameter Example 1 Example 2 Example 3 Mixing time (min) 26 30 20 Screw speed (rpm) 450 350 600 One zone temperature (°C) 170 230 120 Zone temperature (°C) 205 170 240 Three zone temperature (°C) 205 220 185 Four zone temperature (°C) 220 230 240 Five zone temperature (°C) 240 185 225 Six zone temperature (°C) 170 195 230 Seven zone temperature (°C) 190 230 170 Inlet temperature (°C) 200 240 170

The above polymer tests were carried out as follows:

Tensile strength: injection molding 4.0mm tensile test strip, tested according to GB1040-2006;

Elongation at break: injection molded 4.0mm tensile test strip, tested according to GB1040-2006;

Flexural modulus: injection molding 4.0mm, bending test strips, tested according to GB9341-2008;

Combustion performance: Tested according to UL94 using a 4.0 mm sample.

The test results are shown in Table 4:

Tensile strength MPa 143 140 147 Elongation at break % 4 5 3.6 Flexural modulus N/m ² 8467 8201 8556 Warpage (μm) 0.015 0.011 0.01

As can be seen from the above examples, the polymer can maintain good mechanical properties and the improvement in warpage is remarkable.

The low warpage and high hardness polymer of the invention has better impact resistance, chemical resistance, higher hardness and hardness than the conventional engineering plastics, and the hardness is much higher than the hardest polymer at present. POM polyoxymethylene with low warpage is suitable for applications where high precision is required.

The technical means disclosed in the solution of the present invention is not limited to the technical means disclosed in the above embodiments, and further includes a technical solution composed of any combination of the above technical features.

Claims (8)

A low warpage and high hardness polymer characterized by the following composition in terms of weight percent:

A low warpage high hardness polymer according to claim 1, wherein said POK resin comprises POK of all known viscosities. A low warpage high hardness polymer according to claim 1, wherein said compatibilizing agent is a polymer containing a maleic anhydride graft. A low warpage high hardness polymer according to claim 1, wherein said processing aid is an antioxidant. A low warpage high hardness polymer according to claim 4, wherein said antioxidant is 168 or 1010. A low warpage high hardness polymer according to claim 1, wherein the glass fiber has a circular cross section. The low warpage high hardness polymer according to claim 1, wherein the glass fiber has a rectangular cross section; the glass fiber has a non-circular cross section, and the main cross section axis and the second The cross-sectional axis has a dimensional ratio of 2-6, preferably 3-5. A method for preparing a low warpage and high hardness polymer, comprising the steps of: (1) Preparation of raw materials: consisting of the following components in terms of weight percent:

(2) mixing: mixing POK resin, compatibilizer and processing aid in a high mixer for 20-30 min; (3) Extrusion: the mixture after step (2) is fed into the screw extruder from the main feed port, the glass fiber is fed into the screw extruder from the side, and the flame retardant is added to the screw extruder from the lateral or main feed port. The screw speed is 350-600 rpm; the temperature from the head to the feeding port is 120-230 ° C in one zone, 170-240 ° C in the second zone, and the temperature in the three to seven zones is adjusted at 170-240 ° C, and the temperature of the feeding port is 170-240 ° C.