CN114561089A

CN114561089A - PBT/PET alloy and preparation method and application thereof

Info

Publication number: CN114561089A
Application number: CN202210170631.2A
Authority: CN
Inventors: 朱文; 陈平绪; 叶南飚; 莫文杰; 付学俊
Original assignee: Kingfa Science and Technology Co Ltd
Current assignee: Kingfa Science and Technology Co Ltd
Priority date: 2022-02-24
Filing date: 2022-02-24
Publication date: 2022-05-31
Also published as: WO2023160155A1

Abstract

The PBT/PET alloy comprises the following components in parts by weight: 30-50 parts of PBT resin; 13-35 parts of PET resin; 8-15 parts of a brominated flame retardant; 2-5 parts of antimony trioxide; 10-50 parts of glass fiber; based on the total weight of the PBT/PET alloy, each gram of the PBT/PET alloy contains 150-400 micrograms of acetaldehyde. According to the invention, antimony trioxide is used for degrading PET (acetaldehyde content is controlled by controlling the content of each component, temperature setting in the melt extrusion process and retention time of a melt in a screw), meanwhile, the PET resin is promoted to be degraded by using ester exchange reaction of PBT/PET resin in melt processing so as to generate acetaldehyde with specific content, when a resin matrix contains a specific amount of acetaldehyde, the fluidity of the alloy is improved, the polarity is strong, the infiltration and coating of glass fibers are promoted, the fiber floating defect is reduced, the surface smoothness is improved, and the glossiness is obviously improved.

Description

PBT/PET alloy and preparation method and application thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a PBT/PET alloy and a preparation method and application thereof.

Background

The polybutylene terephthalate PBT has excellent electrical property, mechanical strength and processability due to crystallization and linear saturation, and the modified polyester is widely applied to the fields of electronics and electricity and the like. The halogen-free flame-retardant glass fiber reinforced PBT is commonly used as components such as fan frame blades of cooling fans, motor shells, relays, connectors and the like, and is accepted in the industry in a large quantity; compared with PBT, the PET has higher melting point (Tm) and glass transition temperature (Tg), is a linear saturated crystalline polymer, keeps excellent mechanical property in a wider temperature range, has excellent fatigue resistance, aging resistance and electrical insulation property, low energy consumption in production and good processability, and is widely applied to the fields of films, bottle blowing, polyester fibers, engineering plastics and the like.

However, because the flexibility of the PET molecular chain is low, the crystallization speed is slow, the defects that the injection molding period is long, the appearance of the glass fiber-added PET material is obvious in fiber floating, and a good appearance effect can be obtained only by high mold temperature exist, and the like, and the application of various components as appearance parts in the field of engineering plastics is limited because the requirements of the appearance parts, such as low fiber floating, high gloss and the like, are harsh.

A plurality of methods for realizing high gloss of modified polyester are disclosed and reported, and CN2008100377356 discloses that glass fiber reinforced PET is added with additives such as a modified nano reinforcing agent, a nucleating agent, a toughening agent and the like to obtain a high gloss reinforced and toughened PET nano composite material; CN2009100402066 strengthens PBT and PMMA composite glass fiber, and adds compatilizer, nucleating agent, coupling agent and other auxiliary agents to obtain a polyester composite material with the glossiness exceeding 80; CN2009100571261 reports that a glass fiber reinforced PET material is added with a low-viscosity cyclic polyester, a fiber exposure preventing agent TAF (synthetic vegetable oil) and other modification auxiliary agents and nucleating agents to prepare a reinforced polyester material without surface fiber floating and with good glossiness; CN2010105902210 discloses that a glass fiber reinforced PET/PBT alloy is added with an organic and inorganic composite nucleating agent, and cyclic oligomer functional polyester is used as a processing aid to obtain a low-warpage material with good surface glossiness and low longitudinal and transverse shrinkage; CN2015100566108 reports glass fiber reinforced PBT/PP alloy, linear low-density polyethylene is added as a surface brightening agent, and a compatilizer and tackified polyvinyl butyral are used as PBT crystallization inhibitors to obtain a glass fiber reinforced composite material with the glossiness of more than 83; CN2016111751427 discloses that PBT/PET glass fiber reinforced composite material is improved in wetting and coating of resin on glass fiber by adding high-fluidity polybutylene succinate (PBS) resin to improve floating fiber, and high glossiness effect is obtained; CN2018105031305 reports that glass fiber reinforced polyamide compositions obtained by adding nanofillers and hyperbranched polyesters as flow modifiers have higher gloss and less floating fibers. However, the above solutions are all to add other additives to improve the surface gloss, which may change other properties of the composite material to some extent.

Disclosure of Invention

The invention aims to improve the fiber floating degree and the glossiness of a glass fiber reinforced PBT/PET alloy system, and a preparation method and application thereof.

The invention is realized by the following technical scheme:

the PBT/PET alloy comprises the following components in parts by weight:

30-50 parts of PBT resin;

13-35 parts of PET resin;

8-15 parts of a brominated flame retardant;

2-5 parts of antimony trioxide;

10-50 parts of glass fiber;

based on the total weight of the PBT/PET alloy, each gram of the PBT/PET alloy contains 150-400 micrograms of acetaldehyde.

Preferably, the PBT/PET alloy contains 200-350 micrograms of acetaldehyde per gram based on the total weight of the PBT/PET alloy.

More preferably, the PBT/PET alloy contains 300 micrograms of acetaldehyde per gram of the PBT/PET alloy based on the total weight of the PBT/PET alloy.

The detection method of the acetaldehyde content comprises the following steps: using GC-2014 type chromatograph, headspace injector: the temperature of the column furnace is 190 ℃, the temperature of the detector is 280 ℃, and the temperature of the sample injector is 250 ℃; the quantitative method comprises the following steps: external standard method, chromatographic column: the capillary tube of the Carbowax 20M has the length of 60M and the diameter of 0.32 mm; a standard curve was established by accurately injecting 0.2, 0.4, 0.6, 0.8, 1.0. mu.L of pure acetaldehyde solution (1 mg. mL) with 1. mu.L of injection needle^-1) Putting the sample into a headspace bottle filled with nitrogen and sealed, freezing the headspace bottle for 10min in a refrigerator, taking out the headspace bottle, putting the headspace bottle into a headspace sample injector, and measuring peak areas of 5 standard samples under the chromatographic condition to obtain a standard curve of acetaldehyde content; the acetaldehyde content of the test samples was measured using an external standard method.

The average grain diameter of the antimony trioxide is 0.3-2.0 microns.

The average diameter of the glass fiber is in the range of 7-15 microns, and preferably the average diameter of the glass fiber is in the range of 10-13 microns.

In order to further improve the surface gloss, 0-2 parts by weight of D50=0.1-2 microns of talcum powder with average particle size can be further included;

the brominated flame retardant is at least one selected from brominated epoxy resin, brominated polystyrene and brominated polycarbonate.

The surface glossiness of the PBT/PET alloy is more than or equal to 75.

The preparation method of the PBT/PET alloy comprises the following steps: according to the proportion, the components except the glass fiber are uniformly mixed and then fed into a double-screw extruder through a main feeding port, the glass fiber is fed through side feeding and is subjected to melt shearing to obtain the PBT/PET alloy, wherein the maximum temperature range of the screw is 240-260 ℃, the rotating speed range is 300-500rmp, and the retention time is 22-27 s.

The decomposition factors influencing the PET resin are as follows from the beginning to the end: the addition amount of antimony trioxide, the melt processing temperature, the melt residence time, the ratio of PET resin to PBT resin, the average particle size of antimony trioxide and the like. In the embodiment of the invention, the content of acetaldehyde is mainly adjusted by the addition amount of antimony trioxide, the melting temperature and the melting retention time.

The PBT/PET alloy is applied to preparing shells of electronic components and electrical appliances.

The invention has the following beneficial effects:

according to the invention, antimony-containing inorganic compounds are used for degrading PET, meanwhile, ester exchange reaction of PBT/PET two resins during high-temperature melting processing is used for promoting the degradation of PET resin so as to generate acetaldehyde with specific content (150-400 micrograms of acetaldehyde is contained in each gram of PBT/PET alloy), when the resin matrix contains a specific amount of acetaldehyde, the fluidity of the alloy is improved, the polarity is strong, the infiltration and coating of glass fibers are promoted, the fiber floating defect is reduced, and the surface smoothness is improved so that the glossiness is obviously improved.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

The raw material sources used in the examples and comparative examples are as follows:

PBT resin: 1200-211M, chemical engineering of Taiwan Changchun.

PET resin: FG600, characterization of chemical fibers.

Glass fiber A: average diameter of 11 microns, ECS11-4.5-534A, boulder group;

glass fiber B: an average diameter of 10 μm, HMG436S-10-4.0, Tashan glass fibers Co., Ltd;

glass fiber C: average diameter 8 microns, ECS8-03-568H, boulder group;

glass fiber D: average diameter of 14 microns, ECS14-5.0-588, boulder group;

antimony trioxide A: average particle size 0.62 microns;

antimony trioxide B: average particle size 0.30 microns;

antimony trioxide C: average particle size 1.86 microns;

antimony trioxide was purchased from antimony, chenzhou, and screened to obtain samples of different average particle sizes.

Brominated epoxy resin: f-2100, Israel ICL;

brominated polystyrene: saytex 621, yabao;

brominated polycarbonate: BC-58, Kehai.

Talc powder: HTPultra5, Amy mining, D₅₀And 0.65 μm.

Preparation of PBT/PET alloys for the examples and comparative examples: uniformly mixing the components except the glass fiber, feeding the mixture into a double-screw extruder through a main feeding port, feeding the glass fiber in a side feeding manner, and carrying out melt shearing to obtain the PBT/PET alloy, wherein the maximum temperature range of the screw is shown in a table, the rotating speed range is 300-500rmp, and the maximum temperature and the residence time of the screw are shown in the table.

The test methods are as follows:

(1) the detection method of the acetaldehyde content comprises the following steps: using GC-2014 type chromatograph, headspace injector: the temperature of the column furnace is 190 ℃, the temperature of the detector is 280 ℃, and the temperature of the sample injector is 250 ℃; the quantitative method comprises the following steps: external standard method, chromatographic column: the capillary tube of the Carbowax 20M has the length of 60M and the diameter of 0.32 mm; a standard curve was established by accurately injecting 0.2, 0.4, 0.6, 0.8, 1.0. mu.L of pure acetaldehyde solution (1 mg. mL) with 1. mu.L of injection needle^-1) Putting the sample into a headspace bottle filled with nitrogen and sealed, freezing the headspace bottle in a refrigerator for 10min, taking out the headspace bottle, putting the headspace bottle into a headspace sample injector, and measuring peak areas of 5 standard samples under the chromatographic condition to obtain a standard curve of the acetaldehyde content; the acetaldehyde content of the test samples was measured using an external standard method.

(2) Surface gloss: according to ASTM D2457-2013, the test is carried out by injection molding a test specimen with an angle of 60 degrees under the same injection molding process parameters, and the size of the test specimen is 100X 2 mm.

(3) Fiber floating defect: the conditions of fiber floating were visually observed at the same positions of a 100X 2mm square plate: the grade is 5, and the grade 1 is no floating fiber; the level 2 is that the floating fibers are shallow and the number of the floating fibers is 1 to 3; grade 3 is that the floating fiber is lighter and the number is 3-5, but the glossiness is not influenced; the 4 level is that the floating fibers are more and 5-10 in number, which affects the glossiness; the level 5 is fiber floating, which seriously affects the surface gloss.

Table 1: EXAMPLES 1-8PBT/PET ALLOY WITH THE CONTENT OF THE COMPONENTS (IN pbw) AND THE TEST RESULTS

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7	Example 8
									PBT resin	40	40	40	40	40	40	40	40
PET resin	20	20	20	20	20	20	20	20
									Brominated epoxy resins	12	12	12	12	12	12	8	15
Antimony trioxide A	3	3	3	3	3	3	2	5
									Glass fiber A	30	30	30	30	30	30	30	30
Maximum temperature, deg.C	240	250	250	260	260	260	250	250
									Residence time, s	22	23	25	24	26	27	25	25
Acetaldehyde content, microgram/g	152	204	255	297	346	386	188	375
									Surface gloss	75.1	79.3	82.8	81.4	80.2	80.1	78.4	80.6
Float fiber grade	3	3	2	2	2	3	3	3

From examples 1 to 6, it is understood that the acetaldehyde content in the alloy can be controlled by adjusting the maximum temperature and the residence time, and when the acetaldehyde content is in the preferable range, the surface gloss is better and the fiber floating is less.

From example 3/7/8, it is found that by adjusting the content of the flame retardant (mainly aiming at adjusting the content of antimony trioxide), the acetaldehyde content can be significantly changed, and the glossiness and fiber floating of the alloy can be adjusted.

Table 2: examples 9-16 PBT/PET alloy with the respective component contents (in parts by weight) and test results

	Example 9	Example 10	Example 11	Example 12	Example 13	Example 14	Example 15	Example 16
									PBT resin	30	50	40	40	40	40	40	40
PET resin	35	13	20	20	20	20	20	20
									Brominated epoxy resins	12	12			12	12	12	12
Brominated polystyrene			12
									Brominated polycarbonate				12
Antimony trioxide A	3	3			3	3	3	3
									Antimony trioxide B			3
Antimony trioxide C				3
									Glass fiber A	30	30	30	30				30
Glass fiber B					30
									Glass fiber C						30
Glass fiber D							30
									Talcum powder								0.5
Maximum temperature, deg.C	250	250	250	250	250	250	250	250
									Residence time, s	25	25	25	25	25	25	25	25
Acetaldehyde content, microgram/g	292	188	270	239	256	257	253	256
									Surface gloss	78.5	75.7	81.8	80.4	82.5	79.2	80.5	83.2
Float fiber grade	2	3	2	2	2	2	3	2

It can be seen from example 3/9/10 that different levels of PBT/PET resin also significantly affect the acetaldehyde content in the alloy.

From examples 3/11-12, it can be seen that different sizes of antimony trioxide also affect the degradation of PET resin.

From examples 3/13-15, it can be seen that the diameter of the glass fibers has some effect on the surface gloss and the float fiber, but the acetaldehyde content is hardly affected, and in the preferred diameter range, the surface gloss is higher and the float fiber is less.

Table 3: comparative example PBT/PET alloy the contents of the respective Components (in parts by weight) and the test results

	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5	Comparative example 6
							PBT resin	30	50	40	40	40	40
PET resin	40	10	20	20	20	20
							Brominated epoxy resins	12	12	8	12	12	12
Antimony trioxide A	3	3	1	6	3	3
							Glass fiber A	30	30	30	30	30	30
Maximum temperature, deg.C	250	250	250	250	235	265
							Residence time, s	25	25	25	25	20	28
Acetaldehyde content, microgram/g	430	127	93	472	109	478
							Surface gloss	58.3	66.7	43.6	62.5	45.8	61.7
Float fiber grade	5	5	5	4	5	4

As can be seen from comparative example 1, when the PET content is too high, the degradation of PET results in a severe acetaldehyde content of more than 400. mu.g/g, which causes the precipitation of small molecules, increased mold fouling and reduced gloss.

As can be seen from comparative example 2, when the PET content is too low, less PET is degradable, the acetaldehyde content is low, the impregnation effect on the glass fiber is poor, and the surface gloss and the floating fiber are poor.

As can be seen from the comparative example 3, when the antimony trioxide content is too low, the PET resin cannot be effectively degraded, so that the acetaldehyde content is too low, the infiltration effect on the glass fiber is poor, and the surface gloss and the floating fiber are poor.

As is clear from comparative example 4, when the content of antimony trioxide is too high, the acetaldehyde content is too high, which leads to a decrease in surface gloss and deterioration in floating fiber as in comparative example 2.

As can be seen from comparative example 5, when the processing temperature is low and the residence time is insufficient, the PET resin cannot be sufficiently degraded to reach the acetaldehyde content of 150-400. mu.g/g, the surface gloss of the alloy is low and the fiber floating is significant.

From comparative example 6, it is understood that when the processing temperature is too high and the residence time is too long, the acetaldehyde content is too high, which also causes a decrease in the gloss and deterioration in the floating fiber.

Claims

1. The PBT/PET alloy is characterized by comprising the following components in parts by weight:

30-50 parts of PBT resin;

13-35 parts of PET resin;

8-15 parts of a brominated flame retardant;

2-5 parts of antimony trioxide;

10-50 parts of glass fiber;

2. The PBT/PET alloy of claim 1, wherein the PBT/PET alloy comprises 200-350 micrograms of acetaldehyde per gram of the PBT/PET alloy, based on the total weight of the PBT/PET alloy.

3. The PBT/PET alloy of claim 2, wherein the PBT/PET alloy comprises 250-300 μ g acetaldehyde per gram based on the total weight of the PBT/PET alloy.

4. The PBT/PET alloy of any one of claims 1-3, wherein the detection method for acetaldehyde content is: using GC-2014 type chromatograph, headspace sampler: the temperature of the column furnace is 190 ℃, the temperature of the detector is 280 ℃, and the temperature of the sample injector is 250 ℃; the quantitative method comprises the following steps: external standard method, chromatographic column: the capillary tube of the Carbowax 20M has the length of 60M and the diameter of 0.32 mm; a standard curve was established by accurately injecting 0.2, 0.4, 0.6, 0.8, 1.0. mu.L of pure acetaldehyde solution (1 mg. mL) with 1. mu.L of injection needle^-1) Putting the sample into a headspace bottle filled with nitrogen and sealed, freezing the headspace bottle in a refrigerator for 10min, taking out the headspace bottle, putting the headspace bottle into a headspace sample injector, and measuring peak areas of 5 standard samples under the chromatographic condition to obtain a standard curve of the acetaldehyde content; the acetaldehyde content of the test samples was measured using an external standard method.

5. The PBT/PET alloy of claim 1, wherein the antimony trioxide has an average particle size of 0.3 to 2.0 μm.

6. The PBT/PET alloy of claim 1, wherein the glass fiber has an average diameter in the range of 7 to 15 micrometers, preferably in the range of 10 to 13 micrometers.

7. The PBT/PET alloy of claim 1, further comprising, in parts by weight, 0-2 parts D50=0.1-2 microns of an average particle size of talc; the brominated flame retardant is at least one selected from brominated epoxy resin, brominated polystyrene and brominated polycarbonate.

8. The PBT/PET alloy of claims 1-7, wherein the surface gloss of the PBT/PET alloy is not less than 75.

9. Process for the preparation of a PBT/PET alloy according to any one of claims 1 to 8, characterized in that it comprises the following steps: according to the proportion, the components except the glass fiber are uniformly mixed and then fed into a double-screw extruder through a main feeding port, the glass fiber is fed through side feeding and is subjected to melt shearing to obtain the PBT/PET alloy, wherein the maximum temperature range of the screw is 240-260 ℃, the rotating speed range is 300-500rmp, and the retention time is 22-27 s.

10. The use of the PBT/PET alloy of any one of claims 1 to 8 for the manufacture of electronic component housings, electrical appliance housings.