POLYAMIDE MOLDING COMPOSITE MATERIAL, AND PREPARATION METHOD THEREFOR AND APPLICATION THEREOF

Abstract

The present invention provides a semi-aromatic polyamide molding composite material that can be used for producing an LED display screen light source reflection support. Generally, by selecting a semi-aromatic polyamide resin having a specific repeating unit, and enabling the crystallization peak width at half maximum ?T.sub.1/2 to be 4-11? C., the whiteness to be less than 26.5, the reflectivity under a 460 nm light source to be less than 6% etc., the semi-aromatic polyamide molding composite material has the advantages of reduced blue light, high contrast ratio and high gray scale, and can meet requirements for the packaging process and long-term reliability. The package product can be used for manufacturing high-contrast LED display screen light source refection supports for use in multiple environments.

Claims

1. A semi-aromatic polyamide molding composite material, comprising the following components in parts by weight: 40-75 parts of PA10T/X resin; 30-60 parts of wollastonite; and 0.5-4.5 parts of toner; wherein based on a molar percentage of the PA10T/X, a 10T unit accounts for 80-95 mol % and an X unit accounts for 5-20 mol %; wherein the X unit consists of a diacid unit and a diamine unit; the diacid unit is selected from at least one of the group consisting of a terephthalic acid unit, an isophthalic acid unit, 1,6-hexanedioic acid, and a 1,10-decanedioic acid unit; the diamine unit is selected from at least one of the group consisting of a 1,6-hexamethylene diamine unit, a 1,9-nonamethylene diamine unit, a 2-methyl-1,5-pentenediamine unit, a 2-methyl-1,8-octyldiamine unit, a 1,10-diaminodecane unit, and a 1,12-dodecanediamine unit; in a resin matrix of the semi-aromatic polyamide molding composite material, the wollastonite has an average diameter of 4-20 ?m and an average length of 10-250 ?m; a crystallization peak width at half maximum ?T.sub.1/2 of the semi-aromatic polyamide molding composite material is measured to be 4-11? C. by differential scanning calorimetry at a cooling rate of 20? C./min after being heated up to 345? C.; and wherein the semi-aromatic polyamide molding composite material has a whiteness of less than 26.5 and a reflectivity of less than 6% under a 460 nm light source.

2. The semi-aromatic polyamide molding composite material according to claim 1, wherein the PA10T/X resin is selected from at least one of the group consisting of PA10T/10I, PA10T/6T, PA10T/66, PA10T/1010, PA10T/610, PA10T/612, and PA10T/12T.

3. The semi-aromatic polyamide molding composite material according to claim 1, wherein the crystallization peak width at half maximum ?T.sub.1/2 of the semi-aromatic polyamide molding composite material is measured to be 5-8? C. by differential scanning calorimetry at a cooling rate of 20? C./min after being heated up to 345? C.

4. The semi-aromatic polyamide molding composite material according to claim 1, wherein the PA10T/X resin has a number-average molecular weight of 1,500-28,000.

5. The semi-aromatic polyamide molding composite material according to claim 1, wherein in the resin matrix of the semi-aromatic polyamide molding composite material, the wollastonite has the average diameter of 6-13 ?m and the average length of 80-120 ?m.

6. The semi-aromatic polyamide molding composite material according to claim 1, wherein the toner is at least one or a mixture of toners selected from the group consisting of a carbon black toner, a black toner, and an amorphous carbon toner; preferably, the toner is selected from an amorphous carbon toner.

7. The semi-aromatic polyamide molding composite material according to claim 1, wherein the semi-aromatic polyamide molding composite material has a reflectivity of less than 4.5% under a 460 nm light source, and more preferably, the semi-aromatic polyamide molding composite material has a reflectivity of less than 3.8% under a 460 nm light source.

8. The semi-aromatic polyamide molding composite material according to claim 1, further comprising 0-3 parts of an antioxidant in part by weight.

9. A method for preparing the semi-aromatic polyamide molding composite material according to claim 1, comprising the following steps: adding the components to a blender mixer for uniform mixing, extruding and pelleting the mixed components with a twin-screw extruder to obtain the semi-aromatic polyamide molding composite material, wherein a screw temperature ranges from 280? C. to 330? C., and a revolving speed ranges from 400 r/min to 500 r/min.

10. Use of the semi-aromatic polyamide molding composite material according to claim 1, in preparing an LED display screen light source reflection support.

Description

DESCRIPTION OF EMBODIMENTS

[0041] The present invention will be further described with reference to the detailed examples. The following examples will help those skilled in that art further understand the present invention, but are not construed as limiting the scope of the present invention in any form. It should be indicated that those skilled in the art can further make several deformations and improvements in the premise of not departing from the inventive concept. These all fall within the protection scope of the present invention.

[0042] Raw materials used in the examples and comparative examples are as follows.

[0043] Monomers used in the polymerization of the following polyamides are commercially available products which are polymerized pure. [0044] PA10T/1010-1: a 10T unit content of 80 mol %, a number-average molecular weight of 7,500 and a crystallization peak width at half maximum ?T.sub.1/2 of 15.1? C. It was homemade referring to the method of the summary of the present invention; [0045] PA10T/1010-2: a 10T unit content of 85 mol %, a number-average molecular weight of 9,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 16? C. It was homemade referring to the method of the summary of the present invention; [0046] PA10T/1010-3: a 10T unit content of 90 mol %, a number-average molecular weight of 8,500 and a crystallization peak width at half maximum ?T.sub.1/2 of 12.8? C. It was homemade referring to the method of the summary of the present invention; [0047] PA10T/1010-4: a 10T unit content of 95 mol %, a number-average molecular weight of 13,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 8.4? C. It was homemade referring to the method of the summary of the present invention; [0048] PA10T/1010-5: a 10T unit content of 90 mol %, a number-average molecular weight of 4300 and a crystallization peak width at half maximum ?T.sub.1/2 of 14.2? C. It was homemade referring to the method of the summary of the present invention; [0049] PA10T/1010-6: a 10T unit content of 90 mol %, a number-average molecular weight of 21,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 18.3? C. It was homemade referring to the method of the summary of the present invention; [0050] PA10T/1010-7: a 10T unit content of 75 mol %, a number-average molecular weight of 8,800 and a crystallization peak width at half maximum ?T.sub.1/2 of 18.0? C. It was homemade referring to the method of the summary of the present invention; [0051] PA10T/1010-8: a 10T unit content of 97 mol %, a number-average molecular weight of 8,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 7.5? C. It was homemade referring to the method of the summary of the present invention; [0052] PA10T/10I-1: a 10T unit content of 80 mol %, a number-average molecular weight of 10,500 and a crystallization peak width at half maximum ?T.sub.1/2 of 17.1? C. It was homemade referring to the method of the summary of the present invention; [0053] PA10T/10I-2: a 10T unit content of 85 mol %, a number-average molecular weight of 9,800 and a crystallization peak width at half maximum ?T.sub.1/2 of 12? C. It was homemade referring to the method of the summary of the present invention; [0054] PA10T/10I-3: a 10T unit content of 90 mol %, a number-average molecular weight of 8,500 and a crystallization peak width at half maximum ?T.sub.1/2 of 8.3? C. It was homemade referring to the method of the summary of the present invention; [0055] PA10T/10I-4: a 10T unit content of 95 mol %, a number-average molecular weight of 8,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 7.1? C. It was homemade referring to the method of the summary of the present invention; [0056] PA10T/10I-5: a 10T unit content of 60 mol %, a number-average molecular weight of 8,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 15? C. It was homemade referring to the method of the summary of the present invention; [0057] PA10T/66: a 10T unit content of 90 mol %, a number-average molecular weight of 8,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 13.4? C. It was homemade referring to the method of the summary of the present invention; [0058] PA10T/12T: a 10T unit content of 80 mol %, a number-average molecular weight of 8,000 and a crystallization peak width at half maximum ?T.sub.1/2 of 10.6? C. It was homemade referring to the method of the summary of the present invention; [0059] Wollastonite A: an average diameter of 4 ?m and an average length of 60 ?m; [0060] Wollastonite B: an average diameter of 6 ?m and an average length of 120 ?m; [0061] Wollastonite C: an average diameter of 13 ?m and an average length of 80 ?m; and [0062] Wollastonite D: an average diameter of 17 ?m and an average length of 180 ?m. [0063] The wollastonite used in the present invention was purchased commercially and screened to obtain the required ranges of the average diameter and average length. [0064] Talc powder: AH-1250, Guangxi Longsheng Huamei Talc Development Co., Ltd. [0065] Toner A: amorphous carbon toner N774, Tianjin Tianyang Qiushi Chemical Technology Co. LTD. [0066] Toner B: carbon black M570, CABOT Chemical; [0067] Toner C: Black UN2014, CABOT Chemical: [0068] Toner D: Mazcol Blue 153K, Shenzhen Dingtai Chemical Co., LTD. [0069] Antioxidant: Irganox1098, hindered phenol antioxidants.

[0070] Methods for preparing the semi-aromatic polyamide molding composite materials in examples and comparative examples: PA10T/X resin, wollastonite, toner and antioxidants were added to a blender mixer and mixed well, extruded and pelleted with a twin-screw extruder to obtain the semi-aromatic polyamide molding composite material, where the screw temperature ranged from 280?? C. to 330? C., and the revolving speed was 450 r/min.

Test Method:

[0071] (1) Tightness: characterization of the tightness of the support plastic with hardware by red ink testing on the PA10T/X molding composite material sample: a LED reflector cup prepared by a LED display screen light source support material and an electroplating hardware strip in an injection in-molded manner was soaked with red ink to allow the pins to be submerged in the red ink, and placed to observe whether the red ink permeated into the interior of the reflector cup. [0072] If the red ink did not permeate into the reflector cup within 5 min, the tightness grade was determined as level A: [0073] if red ink did not permeate into the reflector cup within 3 min, but permeates within 5 min, the tightness grade was determined as level B; [0074] if red ink did not permeate into the reflector cup within 1 min, but permeates within 3 min, the tightness grade was determined as level C; [0075] if red ink permeates into the reflector cup within 1 min, the tightness grade was determined as level D; and [0076] if the tightness grade was level D, the tightness between plastic and hardware was proved to be poor, which may lead to the risk of lamp bead failure. On the contrary, if the tightness grade was level A, B, or C, the packaged lamp bead has excellent gas tightness and good reliability. [0077] (2) Whiteness: characterization of the contrast ratio of materials via its whiteness index: the PA10T molding composite material was injection molded to prepare a test piece having a length of 60 mm, a width of 60 mm, and a thickness of 1 mm. A Color Eye 7000A color difference meter was used to measure values L, a and b to calculate the whiteness:

[00001]$\mathrm{WH}=100-{\left[{\left(100-L\right)}^2+a^2+b^2\right]}^{1/2}.$ [0078] (3) Reflectivity: the PA10T/X molding composite material was injection molded to prepare a test piece having a length of 60 mm, a width of 60 mm, and a thickness of 1 mm. A Color Eye 7000A color difference meter was used to measure the reflectivity of the test piece to a 460 nm-wavelength light. [0079] (4) Crystallization peak width at half maximum ?T.sub.1/2 of the semi-aromatic polyamide molding composite material: the molding composite material was heated up to 345? C. from 30? C. at a rate of 20? C./min under nitrogen condition; after constant temperature was kept constant for 2 min, the material was cooled at a cooling rate of 20? C./min; the temperature of the crystallization peak emerging at this time was set as a crystallization temperature Tc (? C.), and the temperature at an half of the peak width measured was set as a crystallization peak width at half maximum ?T.sub.1/2.

TABLE-US-00001 TABLE 1 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Examples 1-6 Example Example Example Example Example Example 1 2 3 4 5 6 PA10T/1010-1 60 60 60 60 60 60 Wollastonite A 30 35 40 45 50 60 Toner A 0.5 0.5 0.5 0.5 0.5 0.5 Crystallization 10.6 9.3 8.8 8.1 7.5 7.2 peak width at half maximum ?T.sub.1/2, ? C. Tightness grade B B B B A A Whiteness 26.03 25.77 25.28 24.67 24.01 24.32 Reflectivity, % 5.89 5.44 4.91 4.30 3.81 3.92

[0080] As can be seen from Examples 1-6, when the crystallization peak width at half maximum of the semi-aromatic polyamide molding composite material is controlled within the preferable range by adjusting the amount of the wollastonite added, the tightness grade is higher and the reflectivity is low.

TABLE-US-00002 TABLE 2 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Examples 7-12 Example Example Example Example Example Example 7 8 9 10 11 12 PA10T/1010-1 60 60 60 60 40 75 Wollastonite A 45 45 45 45 30 60 Toner A 1 1.3 1.8 0.5 1 4.5 Toner D 0.8 Crystallization 8.0 8.0 8.0 8.1 7.9 7.7 peak width at half maximum ?T.sub.1/2, ? C. Antioxidant 0.5 Tightness grade B B B B A A Whiteness 22.80 22.26 21.47 23.08 22.37 20.16 Reflectivity, % 3.36 2.94 2.61 3.15 3.08 2.35

[0081] As can be seen from Examples 4/7-10, whiteness and reflectivity are reduced by adjusting the amount of the toner used.

TABLE-US-00003 TABLE 3 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Examples 13-17 Example Example Example Example Example 13 14 15 16 17 PA10T/1010-1 60 60 60 60 60 Wollastonite A 45 45 Wollastonite B 45 Wollastonite C 45 Wollastonite D 45 Toner A 0.5 0.5 0.5 Toner B 0.5 Toner C 0.5 Crystallization 8.2 8.5 8.9 8.1 8.1 peak width at half maximum ?T.sub.1/2, ? C. Tightness grade A A B B B Whiteness 24.28 24.05 24.48 24.89 25.33 Reflectivity, % 3.93 3.69 4.42 4.60 5.13

[0082] As can be seen from Examples 4/13-17, preferably, the wollastonite has an average diameter of 6-14 ?m and an average length of 80-120 ?m; even though the crystallization peak width at half maximum of the composite material is not within the range of 5-8? C., the tightness grade may be further increased and the reflectivity is reduced; the toner is preferably an amorphous carbon toner.

TABLE-US-00004 TABLE 4 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Examples 18-24 Example Example Example Example Example Example Example 18 19 20 21 22 23 24 PA10T/1010-2 60 PA10T/1010-3 60 PA10T/1010-4 60 PA10T/1010-5 60 PA10T/1010-6 60 PA10T/66 60 PA10T/12T 60 Wollastonite A 45 45 45 45 45 45 45 Toner A 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Crystallization 8.7 6.7 4.2 7.8 9.7 7.4 6.1 peak width at half maximum ?T.sub.1/2, ? C. Tightness grade B A B A B A A Whiteness 24.97 23.77 24.38 23.48 24.50 23.62 23.50 Reflectivity, % 4.42 3.96 4.55 3.78 4.33 3.85 3.67

[0083] As can be seen from Examples 4/18-24, by adjusting wollastonite and toner, the semi-aromatic polyamide resin having different initial crystallization peak widths at half maximum enables the crystallization peak width at half maximum to be within different ranges, thus obtaining semi-aromatic polyamide molding composite materials having different tightness grades and reflectivity.

TABLE-US-00005 TABLE 5 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Examples 23-26 Example Example Example Example 23 24 25 26 PA10T/10I-1 60 PA10T/10I-2 60 PA10T/10I-3 60 PA10T/10I-4 60 Wollastonite A 45 45 45 45 Toner A 0.5 0.5 0.5 0.5 Crystallization 8.9 6.6 4.3 4.1 peak width at half maximum ?T.sub.1/2, ? C. Tightness grade B A B B Whiteness 24.84 24.15 24.79 24.89 Reflectivity, % 4.29 3.80 4.32 4.41

TABLE-US-00006 TABLE 6 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Comparative Examples 1-6 Comparative Comparative Comparative Comparative Comparative Comparative Example Example Example Example Example Example 1 2 3 4 5 6 PA10T/1010-7 60 PA10T/1010-8 60 PA10T/10I-5 60 PA10T/1010-1 60 60 60 Wollastonite A 45 45 45 20 70 Talc powder 45 Toner A 0.5 0.5 0.5 0.5 0.5 0.5 Crystallization 9.6 3.9 8.2 9.6 11.2 6.8 peak width at half maximum ?T.sub.1/2, ? C. Tightness grade C D D D D C Whiteness 26.90 24.81 30.14 28.49 27.84 27.40 Reflectivity, % 6.22 4.82 8.60 10.39 6.86 6.75

[0084] As can be seen from Comparative Examples 1/2/3, in the PA10T/X repeating unit, the X content significantly affects the tightness grade; due to the change of the surface property, the reflectivity also increases therewith, and the tightness is affected significantly.

[0085] As can be seen from Comparative Example 4, wollastonite may not be replaced by talc powder.

[0086] As can be seen from Comparative Example 5, too low content of wollastonite may not enable the crystallization peak width at half maximum to be adjusted to be 4-11? C.; the tightness grade is not only poor, but also the reflectivity is high.

[0087] As can be seen from Comparative Example 6, even though the crystallization peak width at half maximum ranges from 4? C. to 11? C., the tightness grade and reflectivity are poor when the content of wollastonite is excessive. This is because too much wollastonite damages the surface structure of the composite material; moreover, as wollastonite is a kind of white powder, too much amount may increase the whiteness on the contrary.

TABLE-US-00007 TABLE 7 components (parts by weight) of the semi-aromatic polyamide molding composite materials and test results in Comparative Examples 7-8 Comparative Comparative Example 7 Example 8 PA10T/1010-1 60 60 Wollastonite A 35 35 Toner A 0.2 5 Crystallization 9.3 9.0 peak width at half maximum ?T.sub.1/2, ? C. Tightness grade B C Whiteness 28.11 21.75 Reflectivity, % 6.41 6.50

[0088] As can be seen from Comparative Example 7, too low content of the toner may lead to a too high whiteness and a high reflectivity.

[0089] As can be seen from Comparative Example 8, too much toner added may lead to the enrichment of too much toner onto the surface, thereby affecting the tightness and reflectivity.