A polycarbonate with wear resistance

Abstract

The present invention provides a polycarbonate, which uses an amide-containing aromatic phenol having the following formula I as an end-capping agent: an amide-substituted aromatic compound is selected as an end-capping agent for controlling the molecular weight of the polymer, thereby preparing a polycarbonate with excellent wear resistance. The polycarbonate has a smooth surface, is wear-resistant and scratch-resistant, and can be used in fields where various complex particles in the air are abraded or frequently rubbed, such as automobile headlights and optical data recording media.

Description

Technical Field

[0001] The invention relates to a polycarbonate with wear resistance, in particular to a polycarbonate with an amide-substituted aromatic terminal structure. Background Art

[0002] Polycarbonate plastics have the advantages of low density, good toughness, easy processing and low price, so they are widely used in high-speed rail windows, aviation transparent parts, optical instruments, automobile light strips, construction and other fields. However, due to structural problems, polycarbonate transparent plastics also have their own disadvantages, such as low surface hardness, poor UV radiation resistance, poor scratch resistance, poor solvent resistance, etc. During use, the surface of polycarbonate is often scratched and scratched due to friction on the outer surface, atmospheric dust or surface cleaning, which affects the transparency and appearance, thereby affecting its service life and limiting its application. Therefore, solving the problem of poor friction resistance of polycarbonate surface has become a research hotspot.

[0003] At present, the most effective way to solve this problem is to blend and modify polycarbonate, or to apply a protective coating on its surface. The main protective layers include organic coatings, organic-inorganic hybrid coatings, inorganic coatings, etc.

[0004] Chinese patent CN103319870A reported a polycarbonate wear-resistant modified plastic, adding 10wt% to 20wt% of polytetraamide ethylene and a certain amount of polyurethane thermoplastic elastomer to polycarbonate, and finally preparing a polycarbonate wear-resistant modified plastic with low friction coefficient, low water absorption, stable size and good self-lubrication. Patent CN109370425A also reported that a wear-resistant coating was applied on the surface of polycarbonate, mainly using tetraethyl orthosilicate, phenyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane to prepare the coating on the surface of the substrate. The coating liquid has good adhesion on the surface of the substrate, a hardness of 4H, excellent wear resistance, and can pass the water boiling test.

[0005] Due to the unevenness of the blending modification and the fact that the coating may fall off the substrate, both methods for improving the wear resistance of polycarbonate materials have certain drawbacks. Summary of the invention

[0006] The present invention provides a polycarbonate with a novel terminal group, which is a polycarbonate prepared by using an amide-substituted aromatic phenol as a terminal blocking agent. The outstanding advantages of the present invention are that the material preparation process is simple and the product has better wear resistance than conventional polycarbonate.

[0007] The present invention provides a polycarbonate, using an amide-containing aromatic phenol having the following formula I as an end-capping agent:

[0008]

[0009] Wherein: the hydroxyl group may be at the meta or para position of the amide structure connected to R1; R1 may be a C1-C4 alkyl group, or an aromatic phenyl group, p-tolyl group, naphthyl group, or a chloromethyl group or a trifluoromethyl group containing heteroatoms, preferably a phenyl group;

[0010] The preferred structure of the amide-containing aromatic phenols is as follows:

[0011]

[0012] The polycarbonate includes homopolymer polycarbonate and copolymer polycarbonate, and generally comprises the structural unit of the following formula II:

[0013]

[0014] Wherein the M1 group is derived from a dihydroxy compound, at least 80% of the total number of M1 groups are aromatic structures, and the rest may be aliphatic or alicyclic structures. Preferably, M1 is an aromatic organic group, more preferably having the structure of the following formula III:

[0015]

[0016] Wherein M2 and M3 are monocyclic aromatic groups, and Y is a bridge group separating M2 and M3; in the above formula, the covalent bond is usually located at the meta or para position between Y and M2 and M3; M2 and M3 may be unsubstituted phenylene or derivatives thereof, preferably unsubstituted phenylene. Although both may be ortho or meta phenylene, or one may be ortho or meta phenylene and the other may be para phenylene, both M2 and M3 are preferably para phenylene;

[0017] The bridging structure Y is a group that separates M2 and M3, most commonly an alkyl group, especially an aliphatic saturated C1-C8 or alicyclic group such as methylene, ethylene, isopropylene, cyclohexylene, cyclododecylene or 2,2-adamantylene, preferably isopropylene;

[0018] The structure of formula III is derived from an aromatic dihydroxy compound (called bisphenol). For the sake of simplicity, the aromatic dihydroxy compound is referred to as bisphenol hereinafter. Due to its effectiveness and particular suitability for the present invention, the bisphenol is preferably bisphenol A, wherein Y is isopropylidene, and both M2 and M3 are p-phenylene;

[0019] The above-mentioned M1 group can also be an aliphatic or alicyclic structure, such as 1,3-propylene glycol, 1,4-butanediol, 2-methyl-1,3-propanediol, cyclohexanedimethanol, and isosorbide.

[0020] The polycarbonate of the present invention can be prepared by the interfacial reaction of phosgene and dihydroxy compounds, wherein amide-substituted aromatic phenols are used as chain end capping agents. The conditions of such reactions are well known in the art, and the main process is to use water and water-incompatible solvents such as dichloromethane as reaction media, tertiary amines or quaternary ammonium salts as catalysts (e.g. triethylamine or tetra-n-butyl ammonium chloride), and also sodium hydroxide to provide an alkaline environment. The proportion of the chain end capping agent is usually 1 to 10 mol%, preferably 1 to 5 mol%, of the proportion of the dihydroxy compound. The polycarbonate of the present invention can also be prepared by other methods, and di-tert-alkylphenol can be converted into carbonate, and the polycarbonate can be prepared by the ester exchange process with the dihydroxy compound.

[0021] In a specific embodiment, the polycarbonate is prepared by the following process:

[0022] Add 1 part by mass of deionized water, 0.05-0.10 parts by mass of sodium hydroxide, 0.15-0.25 parts by mass of bisphenol (preferably bisphenol A) and a capping agent (amide-substituted aromatic phenols) into a glass kettle, purge the glass kettle with nitrogen, and start mechanical stirring to mix evenly to obtain an aqueous phase feed liquid;

[0023] 0.0001-0.0010 parts by mass of catalyst and 1.1-1.5 parts by mass of solvent are used to prepare a mixed solution B; wherein the aqueous phase feed liquid and the mixed solution B can also be directly prepared in the same container;

[0024] The prepared aqueous phase liquid, mixed solution B and 0.11-0.15 parts by weight of phosgene are introduced into the reaction tank at a certain speed, and concentrated alkali solution is continuously added dropwise during the whole process to control the pH of the system between 11 and 13, and the temperature of the reaction liquid is maintained at 20°C to 30°C. Phosgene and bisphenol A continue to react in the reaction tank until the reaction is complete; the concentrated alkali solution is, for example, a 32% by weight sodium hydroxide solution;

[0025] The reaction solution is washed with dilute hydrochloric acid, such as 0.4M hydrochloric acid, and three times with deionized water, and finally precipitated in methanol to obtain a powder. The powder is vacuum dried at 130°C for 10 hours to obtain a dry powder.

[0026] The beneficial effect of the present invention is that amide-substituted aromatic phenols are selected as end-capping agents for controlling the molecular weight of polymers, thereby preparing a polycarbonate with excellent wear resistance. This material can be used in various fields of complex particle abrasion or frequent friction, such as automobile headlights and optical data recording media. DETAILED DESCRIPTION

[0027] The present invention is illustrated by the following examples, but the scope of the present invention is not limited to these examples.

[0028] The molecular weight of polycarbonate was obtained by Agilent Technologies 1260infinity test, with dichloromethane as the mobile phase, a flow rate of 1 mL / min, and the column temperature and the box temperature were both 30°C.

[0029] The injection molding machine used for the production is a Haitian injection molding machine with model number MA900Ⅱ1260.

[0030] The wear resistance of polycarbonate is tested by evenly wiping the surface of the polycarbonate sheet with steel wool, using a 400g weight pressure and a swing speed of 50rpm / min for a total of 10 minutes. The test is conducted using a CSI-101 steel wool wear tester, and the haze is tested using BYK's HAZE-GARD PLUS.

[0031] Example 1

[0032] 7 L of dichloromethane, 8 L of deionized water, 1824 g of bisphenol A, 400 g of sodium hydroxide, 68.3 g of N-(4-hydroxyphenyl)benzamide and 8 mL of triethylamine were added to a 30 L glass kettle, nitrogen was purged into the glass kettle, and mechanical stirring was started.

[0033] After stirring and mixing evenly, 928 g of phosgene was introduced at a rate of 15 g / min, and 32% concentrated alkali solution was continuously added dropwise during the whole process to control the pH of the aqueous phase between 11 and 12. Stirring was continued until the acyl chloride in the solution was completely reacted.

[0034] The oil phase was separated from the reaction solution and washed with 0.4M dilute hydrochloric acid and deionized water in sequence. The polycarbonate was then separated by precipitation with methanol and vacuum dried at 130°C. After drying, it was crushed with a pulverizer to obtain a powder.

[0035] A certain amount of powder was taken for injection molding to prepare a 3 mm thick transparent sheet. After wiping with a CSI-101 steel wool wear tester, the wear resistance test was performed. The results are shown in Table 1 below.

[0036] Example 2-3

[0037] The N-(4-hydroxyphenyl)benzamide in Example 1 was replaced by 2,2,2-trifluoro-N-(4-hydroxyphenyl)acetamide and 4-chloromethyl-4'-hydroxybenzamide in equal moles, respectively, and the experiment was carried out with the other conditions being the same. The results are shown in Table 1.

[0038] Comparative Example 1

[0039] Add 8.5L of dichloromethane, 8L of deionized water, 1824g of bisphenol A, 800g of sodium hydroxide, 48.1g of p-tert-butylphenol and 10mL of triethylamine to a 30L glass kettle. Purge the glass kettle with nitrogen and start mechanical stirring. After stirring and mixing evenly, add 928g of phosgene at a rate of 15g / min. During the whole process, continue to drop 32% concentrated alkali solution to control the pH of the aqueous phase between 11 and 12. Continue stirring until the acyl chloride in the solution reacts completely. Separate the oil phase from the reaction liquid and wash it with 0.4M dilute hydrochloric acid and deionized water in turn. Then use methanol to precipitate and separate the polycarbonate, and vacuum dry it at 130°C. After drying, use a pulverizer to crush it to obtain powder.

[0040] A certain amount of powder was injected to prepare a 3 mm thick transparent sheet. CSI-101 steel wool was evenly wiped on the surface of the polycarbonate sheet to conduct a wear resistance test. The results are shown in Table 1.

[0041] Table 1. Polycarbonate parameters

[0042] Example Capping agent Molecular weight Haze before wiping Haze after wiping 1 N-(4-Hydroxyphenyl)benzamide 26235 0.1％ 2.1％ Comparative Example 1 4-tert-Butylphenol 26750 0.1％ 10.3％ 2 2,2,2-Trifluoro-N-(4-hydroxyphenyl)acetamide 28437 0.3％ 1.2％ 3 4-Chloromethyl-4'-hydroxybenzamide 27001 0.4％ 2.8％

Claims

1. A wear-resistant polycarbonate, characterized in that: Its structure contains amide-containing aromatic phenols derived from the following formula I: Wherein: the hydroxyl group is in the meta or para position of the amide structure connected to R1; R1 is selected from C1-C4 alkyl, phenyl, p-tolyl, naphthyl, chloromethyl, trifluoromethyl.

2. The polycarbonate according to claim 1, characterized in that Contains the structural unit of the following formula II: Wherein the M1 groups are derived from dihydroxy compounds, at least 80 mol% of the total number of M1 groups are aromatic structures.

3. The polycarbonate according to claim 2, characterized in that The aromatic structure M1 has the following structure of formula III: Wherein M2 and M3 are monocyclic aryl groups; Y is an alkyl group.

4. The polycarbonate according to claim 3, characterized in that M2 and M3 are unsubstituted phenylene groups or derivatives thereof; Y is selected from methylene, ethylene, isopropylene, cyclohexylene, cyclododecylene or 2,2-adamantylene.

5. The polycarbonate according to claim 1, characterized in that It is prepared by reacting phosgene with dihydroxy compounds, wherein amide-containing aromatic phenols of formula I serve as chain-capping agents.

6. The polycarbonate according to any one of claims 1 to 5, characterized in that When preparing the polycarbonate, the amount of the amide-containing aromatic phenols of formula I is 1 to 10 mol% of the dihydroxy compound.

7. The polycarbonate according to claim 6, characterized in that When preparing the polycarbonate, the amount of the amide-containing aromatic phenols of formula I is 1 to 5 mol% of the dihydroxy compound.

8. Use of the polycarbonate according to any one of claims 1 to 7 in various fields of complex particle abrasion or frequent friction.

9. The use according to claim 8 in vehicle headlights and optical data recording media.

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