A polyester composition, its preparation and use

Abstract

A polyester composition comprises the following components by weight parts: PCT resin 64-66 parts; white pigment 20-40 parts; reinforcing filler 5-25 parts; cage polysilsesquioxane 0.1-1.2 parts; auxiliary 0-2 parts. The application can not only improve the initial light reflectivity of the polyester composition, but also significantly improve the heat-oxidative aging resistance, hydrolysis resistance and adhesion with glue by adding a specific amount of cage polysilsesquioxane in the polyester composition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular material, in particular to a polyester composition and a preparation method and application thereof. BACKGROUND

[0002] The LED light source is mainly composed of a semiconductor chip, an LED light source reflection support, a gold wire and an encapsulation glue. The LED light source reflection support is the'skeleton' of the LED light source and is also a functional part. In the LED packaging process, the semiconductor chip is fixed, the gold wire is welded, and the encapsulation glue is cured, and other materials and parts are integrated. The LED reflection support needs to reflect the light emitted by the LED chip at a certain angle to reduce light loss, and then pass through the encapsulation material such as epoxy resin or silica gel to form a light source for LED lighting or display. The LED reflection support material is a core material for LED lighting, which directly affects the performance and service life of the LED light source.

[0003] With the increase of chip power, the heat generated inside the light source is greater. If there is a humidity condition at the same time, the LED reflection support plastic may crack, the plastic and glue may peel off, and the problem of dead lamp may occur. SUMMARY

[0004] The purpose of the present application is to overcome the above technical defects and provide a polyester composition with high initial light reflectivity, heat-oxidative aging resistance, hydrolysis resistance and good adhesion to glue.

[0005] The present application is realized by the following technical solutions:

[0006] A polyester composition, by weight, comprises the following components:

[0007] PCT resin 64-66 parts;

[0008] White pigment 20-40 parts;

[0009] Reinforcing filler 5-25 parts;

[0010] Cage polysilsesquioxane 0.1-1.2 parts;

[0011] Auxiliary agent 0-2 parts.

[0012] Preferably, the content of cage polysilsesquioxane is 0.3-0.6 parts.

[0013] The cage polysilsesquioxane is selected from dimethylsilyl cage polysilsesquioxane with CAS number 125756-69-6.

[0014] The white pigment is selected from at least one of titanium dioxide and zinc sulfide.

[0015] The reinforcing filler is selected from at least one of flat glass fiber, round glass fiber, glass flake, wollastonite, potassium titanate, and preferably glass flake. The reason is that the initial light reflectance can be improved when the glass flake is used.

[0016] The PCT resin capable of achieving the object of the present application has a melting point of 260-300°C measured by differential scanning calorimetry at a heating and cooling rate of 20°C / min. In the technical solution of the present application, the weight content of the PCT resin is not less than 42wt%.

[0017] The viscosity of the PCT resin is not particularly limited in the present application, and the object of the present application can be achieved when the intrinsic viscosity is in the range of 0.6-0.9 dl / g. The intrinsic viscosity is measured by using a capillary viscometer, and the test standard is GB / T 14190-2008 (Fiber Grade Polyester Chip).

[0018] The auxiliary agent is selected from at least one of an antioxidant and a lubricant.

[0019] The antioxidant can be: 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; 2,5-di-tert-butyl-4-hydroxybenzyl dimethylamine; diethyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphate; stearyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphate; 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-di-stearyl-thio triazolyl amine; 2,6-di-tert-butyl-4-hydroxymethylphenol; 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylglycol allyl ether)-1,3,5-triazine; N,N'-hexamethylene di(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide); N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine; octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; triethylene glycol di[3-(3,5-dimethyl-4-hydroxyphenyl)propionate]; triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]; 2,2'-thiodiethyl-di[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, etc.

[0020] The lubricant can be at least one of a stearate lubricant, a fatty acid lubricant, and a stearate ester lubricant; the stearate lubricant is at least one of calcium stearate, magnesium stearate, and zinc stearate; the fatty acid lubricant is at least one of a fatty acid, a fatty acid derivative, and a fatty acid ester; and the stearate ester lubricant is at least one of pentaerythritol stearate.

[0021] The flame retardant can be added or not according to actual needs, and the flame retardant is at least one of a dialkyl hypophosphite flame retardant including aluminum diethyl phosphinate, zinc diethyl phosphinate, aluminum methyl ethyl phosphinate, aluminum ethyl butyl phosphinate, or aluminum ethyl hexyl phosphinate.

[0022] The preparation method of the polyester composition comprises the following steps: mixing the components according to the ratio, and then melting and blending through an extruder, and extruding and granulating to obtain the polyester composition; the heating temperature of the extruder is 250-290 DEG C in the first zone, 260-300 DEG C in the second to fourth zones, 270-310 DEG C in the fifth to seventh zones, 260-300 DEG C in the eighth and ninth zones, and 250-290 DEG C in the die head.

[0023] The polyester composition can be applied to the preparation of an LED reflection bracket.

[0024] The polyester composition has the following beneficial effects:

[0025] The polyester composition comprises the cage polysilsesquioxane, and the following technical effects can be achieved:

[0026] 1. The initial light reflectivity of the polyester composition is improved.

[0027] 2. The cage polysilsesquioxane is dispersed in the PCT resin matrix at a nanoscale, so that the material surface is hydrophobic, and the hydrolysis resistance of the PCT is improved.

[0028] 3. The cage polysilsesquioxane is dispersed at a nanoscale, the Si-O-Si structure is stable, a dense silicon oxide film layer is formed at high temperature, oxygen and heat can be effectively blocked from transferring to the inside of the polymer, and the thermal stability of the polymer material is improved.

[0029] 4. The cage polysilsesquioxane has good reactivity and compatibility, and the adhesion of the PCT and the silica encapsulation adhesive is improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 : Schematic diagram for testing the adhesion of the silica encapsulation adhesive. DETAILED DESCRIPTION

[0031] The application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the application. These are within the scope of the present application.

[0032] The raw materials used in the present application are as follows:

[0033] PCT resin A: PCT0502, melting point 290℃, manufacturer: SK Chemicals, Korea;

[0034] PCT resin B: PCT0502HC, melting point 295℃, manufacturer: SK Chemicals, Korea;

[0035] Dimethylsilyl cage polysilsesquioxane: Dimethylsilyl POSS, manufacturer: Forsman Technology (Beijing) Co., Ltd.;

[0036] Linear polysilsesquioxane: MY 1203M, manufacturer: Anhui Mingyi Silicon Industry Co., Ltd.;

[0037] Flat glass fiber: ECS301HP-3-M3, manufacturer: CPIC;

[0038] Round glass fiber: ECS10-03-568H, manufacturer: JUSHI;

[0039] Glass flake: C-150, manufacturer: Glassflake, UK;

[0040] Wollastonite: NYGLOS 8, manufacturer: YiRuiShi, USA;

[0041] Titanium dioxide: CR-211, manufacturer: Zhongxin Titanium Industry Co., Ltd.;

[0042] Antioxidant: RIANOX 1010, manufacturer: Tianjin Li'An Long New Material Co., Ltd.;

[0043] Lubricant: PETS AHS, manufacturer: Italmatch;

[0044] Preparation method of polyester composition in examples and comparative examples: according to the proportion, the components are mixed, then melt blended, extruded and granulated by an extruder to obtain the polyester composition; the heating temperature of the extruder is 250-290℃ in zone 1, 260-300℃ in zones 2-4, 270-310℃ in zones 5-7, 260-300℃ in zones 8-9 and 250-290℃ in the die head.

[0045] Test methods:

[0046] (1) Light reflectance: Test pieces of 60 mm in length, 60 mm in width, and 1 mm in thickness were prepared by injection molding of the polyester composition. The reflectance Rf-460nm of the test pieces for light of 460 nm wavelength was measured using a Color Eye 7000A color difference meter.

[0047] (2) Heat-oxidation resistance: The retention rate M of the bending strength after a high-temperature aging test at 180°C was used as an index.

[0048] Bending strength retention rate M (%) = A / B*100%

[0049] A is the bending strength measured after high-temperature aging at 180°C for 168 h, and B is the bending strength measured under normal temperature conditions.

[0050] (3) Hydrolysis resistance: The retention rate N of the tensile strength after a boiling test was used as an index.

[0051] Tensile strength retention rate N (%) = C / D*100%

[0052] C is the tensile strength measured after boiling at 80°C for 168 h, and D is the tensile strength measured under normal temperature conditions.

[0053] (4) Adhesion of silicone encapsulating glue: As shown in the attached drawing, two ASTM bars made of the polyester composition were adhered with silicone (Kangmeite 1608 specification), the adhering area was 10 x 12.7 mm, and the tensile strength S of the adhered bars was tested. Figure 1

[0054] Table 1: Components (parts by weight) of the polyester compositions of Examples 1-7 and test results

[0055] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PCT resin A 65 65 65 65 65 65 PCT resin B 65 Titanium dioxide 30 30 20 40 30 30 30 Glass flake 10 10 5 25 10 10 10 Dimethylsilyl cage polysilsesquioxane 0.3 0.3 0.1 0.8 0.1 0.6 1.2 Antioxidant 0.2 0.2 0 0.2 0.2 0.2 0.2 Lubricant 0.1 0.1 0 0.1 0.1 0.1 0.1 Light reflectance, Rf-460 nm (%) 93.1 93.2 91.3 94.0 90.5 93.8 93.0 Thermo-oxidative aging flexural strength retention M (%) 89.1 90.2 84.0 91.2 85.1 90.5 88.9 Hydrolysis test tensile strength retention N (%) 85.2 86.0 85.3 89.4 84.3 87.8 86.2 Adhesive bonding strength S (MPa) 30 30 24 34 23 32 28

[0056] As can be seen from Examples 1 / 5-7, with the increase of the content of the dimethylsilyl cage polysilsesquioxane, the above-mentioned properties are improved, but when the content reaches 0.6, the improvement slows down, and if the content of the cage polysilsesquioxane is further increased, the properties will be reduced.

[0057] Table 2: Components (parts by weight) of the polyester compositions of Examples 8-10 and Comparative Examples and test results

[0058] Example 8 Example 9 Example 10 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 PCT resin A 65 65 65 65 65 65 65 65 Titanium dioxide 30 30 20 30 30 30 30 30 Glass flake 10 10 10 2 33 Flat glass fiber 10 Round glass fiber 10 Wollastonite 10 Dimethylsilyl cage polysilsesquioxane 0.3 0.3 0.3 0 1.5 0.3 0.3 Linear polysilsesquioxane 0.3 Antioxidant 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Lubricant 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Light reflectance, % 93.0 92.7 90 90.0 91.0 85 93.9 87.1 Thermo-oxidative aging flexural strength retention M (%) 87.6 86.0 82.3 75.0 84.6 70 76 90.2 Hydrolysis test tensile strength retention N (%) 84.0 85.0 83.6 70.0 82.4 65 63 86.5 Adhesive bonding strength S (MPa) 30 29 23 15 27 18 32 23.4

[0059] As can be seen from Examples 1 / 8-10, the reinforcing filler is preferably glass flake.

[0060] ​From the above examples, the initial light reflectivity of the polyester composition is ≥90%, the heat aging bending strength retention rate is ≥82%, the hydrolysis test tensile strength retention rate is ≥83%, and the glue bonding strength is ≥23 MPa.

[0061] As can be seen from Comparative Example 1-2, when the cage-shaped poly-silsesquioxane is not contained, the performance is poor; when the content of the cage-shaped poly-silsesquioxane is too high, the performance is reduced, especially the light reflectivity is reduced, and it is not suitable for use as an LED reflection support.

[0062] As can be seen from Comparative Example 3, the linear poly-silsesquioxane cannot achieve the technical effects of the present application.

[0063] As can be seen from Comparative Example 4, when the content of the glass flake is too low, the heat aging property and the hydrolysis resistance of the composition are mainly affected.

[0064] As can be seen from Comparative Example 5, when the content of the glass flake is too high, the resin is easily sheared and damaged in the processing process of the screw, resulting in a reduction in the light reflectivity; however, due to the excessive content of the filler and the reduction in the proportion of the resin, the glue bonding strength is significantly reduced.

Claims

1. A polyester composition, characterized in that, By weight, it includes the following components: 64-66 parts of PCT resin; 20-40 parts white pigment; 5-25 parts of reinforcing filler; 0.3-0.8 parts of cage-like polysilsesquioxane; 0-2 parts of auxiliary agent; The reinforcing filler is selected from glass flakes.

2. The polyester composition according to claim 1, characterized in that, The content of cage-shaped polysilsesquioxane is 0.3-0.6 parts.

3. The polyester composition according to claim 1, characterized in that, The white pigment is selected from at least one of titanium dioxide and zinc sulfide.

4. The polyester composition according to claim 1, characterized in that, The melting point of the PCT resin is 260-300℃.

5. The polyester composition according to claim 1, characterized in that, The additives are selected from at least one of antioxidants and lubricants.

6. The polyester composition according to claim 1, characterized in that, The cage-like polysilsesquioxane is selected from dimethylsilyl cage-like polysilsesquioxane.

7. A method for preparing the polyester composition according to any one of claims 1-6, characterized in that, According to the formula, the components are mixed and then melt-blended and extruded into granules through an extruder to obtain a polyester composition; wherein the heating temperature of the extruder is 250-290℃ in zone 1, 260-300℃ in zones 2-4, 270-310℃ in zones 5-7, 260-300℃ in zones 8-9 and 250-290℃ at the die head.

8. The use of the polyester composition according to any one of claims 1-6, characterized in that, Used to manufacture LED reflector brackets.

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