Rapidly crystallized PET (Polyethylene Terephthalate) composition as well as preparation method and application thereof

Abstract

The invention relates to a quickly crystallized PET (Polyethylene Terephthalate) composition as well as a preparation method and application thereof in the field of high polymer materials. The rapidly crystallized PET composition is prepared from PET resin and a compound nucleating agent, the compound nucleating agent comprises a maleic anhydride copolymer alkali metal modifier and alkali metal modified PET (Polyethylene Terephthalate); the maleic anhydride copolymer alkali metal modifier is obtained by combining alkali metal ions after acid anhydride of a maleic anhydride copolymer is subjected to ring opening; and acid anhydride of the maleic anhydride copolymer is combined with alkali metal ions after ring opening. The weight ratio of the PET resin to the compound nucleating agent is 100: (0.1-15); the maleic anhydride copolymerization modifier and the PET-containing nucleating agent master batch are compounded, so that the crystallization temperature and the crystallization speed of PET can be improved, and the cold crystallization temperature can be eliminated.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more specifically, to a rapidly crystallizing PET composition, its preparation method, and its applications. Background Technology

[0002] Polyethylene terephthalate (PET) possesses excellent properties such as high rigidity, electrical insulation, heat resistance, and chemical resistance, and has been widely used in fiber, film, and food packaging. However, due to its slow crystallization rate, high demolding temperatures can lead to incomplete and uneven crystallization, causing products to easily stick to the mold and exhibiting disadvantages such as warping, rough and dull surface, poor impact resistance, and poor resistance to damp heat, thus limiting its use in engineering fields.

[0003] Adding nucleating agents is the most common and effective method to improve crystallization rate and shorten molding cycle. Currently, nucleating agents widely used in PET fall into two main categories: inorganic and organic. Inorganic nucleating agents function through heterogeneous nucleation; their addition lowers the free energy barrier required for crystal formation to reach the critical size, thus increasing the crystallization rate of PET. Organic nucleating agents function through homogeneous nucleation; they react with PET ester bonds to form a PET macromolecular backbone terminated in carboxylic acid metal salts, which serve as nucleation sites, inducing the crystallization of the PET molecular backbone. Research has shown that organic nucleating agents have relatively higher nucleation efficiency, and many scholars have conducted related research in this area.

[0004] Jiang et al. (Influence of Surlyn on the Rheological and Crystallization Properties of PET and its Blends. China Plastics, 2020, 34(07):44-48.DOI:10.19491 / j.issn.1001-9278.2020.07.007.) prepared blends of polyethylene terephthalate (PET) / polyamide 6 (PA6) and Surlyn by melt blending. The results showed that Surlyn can improve the melt strength of the PET / PA6 / Surlyn blend system, promote the crystallization of PET in the blend system, increase the crystallization temperature of PET by 10℃, and significantly reduce the supercooling and half-width at half-maximum of crystallization. Zhong Xiaoliang et al. (Synthesis of styrene-sodium methacrylate ionomer and its effect on PET crystallization behavior [J]. China Plastics, 2011, 25(11): 56-60.) studied the crystallization / melting behavior of styrene-sodium methacrylate on PET and found that adding 1% can increase the crystallization temperature of PET by 17.9℃ and decrease the cold crystallization temperature by 17.3℃. JP5548985B2 discloses a composition of PET with a specific aliphatic dicarboxylic acid disodium salt and ionomer resin. The crystallization rate of the resulting composition is improved, and the melt viscosity and impact strength are significantly improved. US4357268A discloses a nucleating agent for a composition of dimer salt, trimer salt or a mixture of dimer acid and trimer acid salt, which is suitable for PET crystallization. CN101709121B proposes a composite nucleating agent of ultrafine mineral powder, solid polyethylene glycol, ionomer and sodium benzoate. When introduced into PET, it can achieve the effects of fast crystallization, low mold temperature and high heat resistance. The nucleating agents used in the above-mentioned existing technologies have problems such as high preparation difficulty and insufficient modification effect.

[0005] Currently, the application of nucleating agents in modified PET materials is limited in China, mainly because the domestic PET nucleating agent system is not yet perfect. Some nucleating agents, due to their high melting points, do not melt within the PET processing temperature range, resulting in poor dispersion and nucleation effects. Other nucleating agents in research, while improving the crystallization properties of PET, cannot eliminate cold crystallization. Therefore, developing a PET nucleating agent system with high nucleation efficiency and good dispersibility is of significant practical importance. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention proposes a rapidly crystallizing PET composition. Specifically, it relates to a rapidly crystallizing PET composition, its preparation method, and its applications. The proposed solution combines a maleic anhydride copolymer modifier with a nucleating agent masterbatch containing PET, which can increase the crystallization temperature and crystallization rate of PET and eliminate cold crystallization temperature.

[0007] One object of the present invention is to provide a rapidly crystallizing PET composition comprising PET resin and a compounding nucleating agent.

[0008] The weight ratio of the PET resin to the compound nucleating agent is 100:(0.1-15), preferably 100:(0.2-10). For example, it can be 100:01, 100:0.5, 100:1.0, 100:1.2, 100:1.4, 100:2.0, 100:2.5, 100:3.0, 100:3.5, 100:4.0, 100:4.5, 100:5.0, 100:5.5, 100:6.0, 100:6.5, 100:7.0, 100:7.5, 100:8.0, 100:8.5, 100:9.0, 100:9.5, 100:10.0, 100:11, 100:12, 100:13, 100:14, 100:15, or any value between the above values ​​or a range of values ​​between any two of the above values, such as 100:(1-8).

[0009] The compound nucleating agent includes maleic anhydride copolymer alkali metal modified and alkali metal modified PET.

[0010] According to a preferred embodiment of the present invention, the weight ratio of the maleic anhydride copolymer alkali metal modified product and the alkali metal modified PET is 1:(1-100), preferably 1:(1-50), for example, it can be 1:1, 1:2, 1:4, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20, 1:25, 1:28, 1:30, 1:32, 1:35, 1:38, 1:40, 1:45, 1:48, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, 1:100 or any value between the above values ​​or a range between any two of the above values, for example, 1:(5-50).

[0011] The alkali metal modified maleic anhydride copolymer is obtained by combining alkali metal ions after ring opening of the maleic anhydride copolymer.

[0012] The maleic anhydride copolymer used in the alkali metal modified maleic anhydride copolymer can be any maleic anhydride copolymer already available in the prior art, preferably an alternating maleic anhydride copolymer, more preferably at least one of linear alternating maleic anhydride copolymers, and even more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M is selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction, more preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

[0013] The C4 olefins, C5 olefins, C8 olefins, and C9 olefins refer to olefins or mixtures of olefins that each contain 4, 5, 8, or 9 carbon atoms. For example, a C4 olefin may be a mixture of one or more olefins containing 4 carbon atoms; a C5 olefin may be a mixture of one or more olefins containing 5 carbon atoms; a C8 olefin may be a mixture of one or more olefins containing 8 carbon atoms; and a C9 olefin may be a mixture of one or more olefins containing 9 carbon atoms.

[0014] The C4 and C5 fractions are selected from C4 or C5 fractions from the oil refining or ethylene industry, preferably from C4 or C5 fractions obtained from ethylene cracking in the petrochemical industry; the C8 and C9 fractions are selected from C8 or C9 fractions from the steam cracking process for ethylene production in the petrochemical industry, the naphtha platinum reforming process, and coal tar.

[0015] The structural characteristics of the alkali metal modified maleic anhydride copolymer are as follows: the maleic anhydride in the maleic anhydride copolymer reacts with an alkali metal inorganic salt, and each maleic anhydride ring-opening compound is linked to one and / or two alkali metal ions. Specifically, the alkali metal may be selected from at least one of lithium, sodium, potassium, rubidium, cesium, and francium, more preferably at least one of lithium, sodium, and potassium.

[0016] According to specific embodiments of the present invention, the weight fraction of alkali metal elements in the maleic anhydride copolymer alkali metal modified product can be 1%-22%, preferably 2%-20%. Specifically, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between the above values ​​or a range between any two of the above values, such as 3%-15%, 5%-16%, etc.

[0017] According to specific embodiments of the present invention, the morphology of the maleic anhydride copolymer alkali metal modified material may also be spherical or near-spherical. Preferably, the average particle size of the maleic anhydride copolymer alkali metal modified material is 2-15 μm, more preferably 4-12 μm. For example, it can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or any value between the above values ​​or a range between any two of the above values, such as 4-10 μm.

[0018] The structural feature of the alkali metal modified PET is that alkali metal ions are attached to the end groups of the PET molecular chain, which can be obtained by reacting PET with alkali metal inorganic salts.

[0019] According to a specific embodiment of the present invention, the weight content of alkali metal elements in the alkali metal modified PET can be 0.05%-1%, preferably 0.05%-0.5%, more preferably 0.05%-0.3%; for example, it can be 0.05%, 0.08%, 0.1%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or any value between the above values ​​or a range between any two of the above values, such as 0.1%-0.3%.

[0020] A second objective of this invention is to provide a method for preparing the rapidly crystallizing PET composition, which may include the following steps:

[0021] The components, including the compound nucleating agent and PET resin, are blended and processed to obtain the rapid crystallization PET composition.

[0022] The method may specifically include blending the prepared maleic anhydride copolymer alkali metal modified product, alkali metal modified PET, and other components with PET resin, and then obtaining the rapid crystallization PET composition by thermoplastic processing.

[0023] More specifically, the method for preparing the rapidly crystallizing PET composition may include the following steps:

[0024] (1) Preparation of compound nucleating agent: Mix the components including maleic anhydride copolymer alkali metal modified and alkali metal modified PET to obtain compound nucleating agent;

[0025] (2) After blending PET resin with a compound nucleating agent, the mixture is melt-processed to obtain the rapid crystallization PET composition.

[0026] in,

[0027] In step (1),

[0028] The compound nucleating agent includes the maleic anhydride copolymer alkali metal modified and the alkali metal modified PET.

[0029] The ratio of the maleic anhydride copolymer alkali metal modified product and the alkali metal modified PET has a wide selection range. Specifically, the weight ratio of the maleic anhydride copolymer alkali metal modified product and the alkali metal modified PET can be 1:(1-100), preferably 1:(1-50).

[0030] The preparation method of the maleic anhydride copolymer alkali metal modified material may include the following steps:

[0031] An alkali metal inorganic salt is dissolved in water, and then a maleic anhydride copolymer is added. The mixture is reacted to obtain a solution, which is then dried to obtain the alkali metal-modified maleic anhydride copolymer. The alkali metal-modified maleic anhydride copolymer can optionally undergo conventional treatment, such as grinding, before use.

[0032] The reaction involves the acid-base neutralization reaction between the anhydride groups of the maleic anhydride copolymer and an alkali metal inorganic salt. The reaction is stopped once a homogeneous solution is formed. There are no particular limitations on the reaction temperature and pressure; the reaction temperature can be 5–95°C, preferably room temperature; the reaction pressure is preferably atmospheric pressure. There are also no particular limitations on the equipment used for the reaction; conventional solution reaction equipment from the prior art can be used.

[0033] The amount of maleic anhydride copolymer used can be 0.1%-30% of the total weight of the solution, preferably 0.1%-15%, more preferably 0.1%-10%. For example, it can be 0.1%, 0.5%, 1.0%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, or any value between the above values ​​or a range between any two of the above values.

[0034] According to a specific embodiment of the present invention, the molar ratio of the maleic anhydride copolymer (calculated by anhydride groups) to the alkali metal inorganic salt (calculated by alkali metal element) can be 1:(0.1-4), preferably 1:(0.2-3), more preferably 1:(0.5-2.5); for example, it can be 1:0.1, 1:0.2, 1:0.4, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2.0, 1:2.2, 1:2.5, 1:2.8, 1:3.0, 1:3.2, 1:3.5, 1:3.8, 1:4.0 or any value between the above values ​​or a range between any two of the above values, such as 1:(0.2-2), 1:(0.5-2), etc.; the reaction is an acid-base neutralization reaction between the anhydride groups of the maleic anhydride copolymer and the alkali metal inorganic salt.

[0035] The drying method is selected from at least one of vacuum drying, hot drying, freeze drying, and spray drying, preferably at least one of hot drying and spray drying, and more preferably spray drying.

[0036] The temperature of the heat drying can be 75℃-150℃, more preferably 80-95℃.

[0037] The inlet air temperature of the spray dryer can be 150℃-200℃, preferably 155℃-180℃; the outlet air temperature can be 60℃-100℃, preferably 70℃-95℃.

[0038] When spray drying is used, the viscosity of the solution can be less than 100 mPa·s, preferably less than 80 mPa·s, more preferably less than 70 mPa·s, for example, preferably less than 60 mPa·s, and even more preferably less than 50 mPa·s. Specifically, it can be any value between the above values, or a range between any two of the above values, such as 5, 10, 15, 20, 25, 30, 40, 45, 50, 60, 65, 70, 80, 85, 90, and 95 mPa·s. The viscosity can be tested using conventional instruments in the art. The testing equipment and method used here are: Fangrui NDJ-5S equipment, using a #2 rotor at a speed of 60 RPM.

[0039] When spray drying is used, the amount of maleic anhydride copolymer added is 0.1%-15% of the total weight of the resulting solution, preferably 0.1%-10%. Specifically, it can be 0.1%, 0.5%, 1.0%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between the above or any two of the above values, such as 3%-10%.

[0040] When spray drying is used, the number average molecular weight of the maleic anhydride copolymer is preferably less than 30,000 g / mol, more preferably less than 25,000 g / mol. For example, it can be any value between the above values, such as 5,000, 8,000, 10,000, 15,000, 18,000, 20,000, 22,000, 25,000, 29,000, 29,500 g / mol, or a range between any two of the above values, such as 5,000–29,500 g / mol, 10,000–29,500 g / mol, 15,000–25,000 g / mol, etc.

[0041] When spray drying is used, the maleic anhydride copolymer may be selected from linear maleic anhydride copolymers.

[0042] In a specific embodiment of the present invention, the alkali metal modified maleic anhydride copolymer obtained by spray drying has a spherical or near-spherical morphology. The product obtained by spray drying has a small particle size, does not agglomerate, and has good dispersibility. Its average particle size can be 2-15 μm, preferably 4-12 μm. For example, it can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or any value between the above values ​​or a range between any two of the above values, such as 4-10 μm.

[0043] in,

[0044] The range of alkali metal inorganic salts used in this application is relatively wide. In specific embodiments of the present invention, the alkali metal inorganic salt can be selected from at least one of alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal sulfates, and alkali metal nitrates, preferably at least one of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, more preferably at least one of alkali metal hydroxides, and even more preferably sodium hydroxide.

[0045] The maleic anhydride copolymer can be any maleic anhydride copolymer already available in the prior art, preferably an alternating maleic anhydride copolymer, more preferably at least one of linear alternating maleic anhydride copolymers, and even more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M can be selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction; preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

[0046] The C4 olefins, C5 olefins, C8 olefins, and C9 olefins refer to olefins or mixtures of olefins that each contain 4, 5, 8, or 9 carbon atoms. For example, a C4 olefin may be a mixture of one or more olefins containing 4 carbon atoms; a C5 olefin may be a mixture of one or more olefins containing 5 carbon atoms; a C8 olefin may be a mixture of one or more olefins containing 8 carbon atoms; and a C9 olefin may be a mixture of one or more olefins containing 9 carbon atoms.

[0047] The C4 and C5 fractions are selected from C4 or C5 fractions from the oil refining or ethylene industry, preferably from C4 or C5 fractions obtained from ethylene cracking in the petrochemical industry; the C8 and C9 fractions are selected from C8 or C9 fractions from the steam cracking process for ethylene production in the petrochemical industry, the naphtha platinum reforming process, and coal tar.

[0048] The preparation method of the alkali metal modified PET may include the following steps:

[0049] PET resin is melt-blended with components including alkali metal inorganic salts to obtain alkali metal modified PET.

[0050] The melt blending described herein employs conventional melt blending conditions in the art, such as a temperature of 180-270℃, which can be adjusted according to actual conditions. The alkali metal modified PET has a wide particle size range, which can be the conventional melt blending granulation particle size, and can be adjusted according to actual needs.

[0051] The weight ratio of the PET resin to the alkali metal inorganic salt can be 100:(0.05-15), preferably 100:(0.1-10). For example, it can be 100:0.05, 100:0.1, 100:0.2, 100:0.25, 100:0.3, 100:0.4, 100:0.5, 100:1.0, 100:1.2, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15, or any value between the above values ​​or a range of values ​​between any two of the above values, such as 100:(0.1-5), 100:(0.1-2), etc.

[0052] The alkali metal modified PET has a wide range of alkali metal element content. In a specific embodiment of the present invention, the weight content of alkali metal element can be 0.05%-1%, preferably 0.05%-0.5%, and more preferably 0.05%-0.3%.

[0053] In step (2),

[0054] The ratio of PET resin to compound nucleating agent can be selected over a wide range. Specifically, the weight ratio of PET resin to compound nucleating agent can be 100:(0.1-15), preferably 100:(0.2-10).

[0055] The PET resin used in this application has a wide range of choices, and can be selected from various PET resins in the prior art, including PET copolymer resins.

[0056] The melting process described in step (2) is a conventional technique in the art. For example, the temperature can be 180-270℃. The melting process conditions can be adjusted according to the actual situation, which will not be elaborated here.

[0057] In a specific implementation, the method for preparing the rapidly crystallizing PET composition may include the following steps:

[0058] (a) Preparation of maleic anhydride copolymer alkali metal modified product: Dissolve alkali metal inorganic salt in water, add maleic anhydride copolymer solid, react fully to obtain a solution, dry it, and that is the maleic anhydride copolymer alkali metal modified product.

[0059] (b) Preparation of alkali metal modified PET: PET resin is melt-blended with alkali metal inorganic salt to obtain alkali metal modified PET;

[0060] (c) Preparation of compound nucleating agent: The components, including maleic anhydride copolymer alkali metal modified and alkali metal modified PET, are mixed to obtain compound nucleating agent;

[0061] (d) After blending PET resin with a compound nucleating agent, the mixture is melt-processed to obtain the rapid crystallization PET composition.

[0062] During the research and development of the compound nucleating agent used in the rapid crystallization PET composition of this invention, it was discovered that maleic anhydride copolymer with alkali metal modification has excellent nucleating ability, but due to its poor melting ability, it is prone to uneven dispersion in PET resin. Alkali metal modified PET can be melt-processed and also has excellent nucleating ability for PET, but experiments showed that when alkali metal modified PET is blended with PET, it cannot effectively eliminate the cold crystallization of PET. The inventors discovered in experiments that using maleic anhydride copolymer with alkali metal modification and alkali metal modified PET in combination not only complements the problems of both as nucleating agents, but also synergistically improves the crystallization improvement effect of PET when used alone as a nucleating agent.

[0063] A third objective of this invention is to provide a PET composition product obtained by the preparation method described in the second objective of this invention.

[0064] A fourth objective of this invention is to provide applications of the rapid crystallization PET composition described herein, specifically, applications in the field of injection molded products.

[0065] The inventors of this application discovered in their research that, when PET resin is blended with the alkali metal-modified maleic anhydride copolymer and the alkali metal-modified PET nucleating agent described in this invention, a rapidly crystallizing PET composition can be obtained within the specific ratio range of this invention. The main advantages of this invention are:

[0066] (1) The raw materials for the maleic anhydride copolymer are readily available and the industrial production process is mature;

[0067] (2) The raw materials and preparation processes used in the alkali metal modified maleic anhydride copolymer are industrially mature and easy to promote industrially.

[0068] (3) The raw materials, equipment and methods involved in the alkali metal modified PET are all mature, and the cost is low and the nucleation effect is obvious;

[0069] (4) The alkali metal modified PET can assist the dispersion of the maleic anhydride copolymer alkali metal modifier in PET resin, and the synergistic effect of the two makes the crystallization performance of PET more significantly improved. Attached Figure Description

[0070] Figure 1 This is a scanning electron microscope image of the alkali metal modified maleic anhydride copolymer obtained in Example 4. Detailed Implementation

[0071] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0072] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0073] Source of raw materials

[0074] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0075] 1. The raw materials used in the examples and comparative examples include:

[0076] Maleic anhydride, styrene, isoamyl acetate, azobisisobutyronitrile, and sodium hydroxide were all purchased from Inokai, analytical grade; mixed C4 was from Zhenhai Refining & Chemical; PET was from Yizheng Chemical Fiber, BG85.

[0077] The maleic anhydride-styrene linear alternating copolymer (MSL) used in the examples was prepared according to the method described in the published literature (A new family of thermoplastic photoluminescence polymers. Polym. Chem., 2016, 7, 6250-6256). The main preparation conditions and parameters were as follows: the molar ratio of maleic anhydride to styrene was 1:1; the medium was isoamyl acetate; the initiator was azobisisobutyronitrile; the ratio of monomer to medium was (0.05-0.5):1; the reaction temperature was (50℃-85℃); and the reaction time was (0.5h-12h). The molecular weight was adjusted by adjusting the reaction concentration, temperature, and time to prepare maleic anhydride-styrene linear alternating copolymers (MSL) with number average molecular weights of 23800 g / mol, 42000 g / mol, and 19800 g / mol, respectively, for later use.

[0078] The maleic anhydride-C4 linear alternating copolymer (MC4L) used in the examples was prepared according to the method described in Example 1 of Chinese Patent Publication No. CN107722177A. The main preparation conditions and parameters were as follows: the reaction monomers were maleic anhydride (20 kg) and mixed C4A (14 kg); the medium was isoamyl acetate (100 L); and the initiator was azobisisobutyronitrile (2.4 kg). The composition (weight percentage) of the mixed C4A was as follows: 1,2-butadiene, 8.92%; 1,3-butadiene, 14.14%; 1-butene, 8.38%; trans-2-butene, 5.84%; cis-2-butene, 31.7%; vinylacetylene, 10.99%; isobutane, 1.3%; isobutene, 12.78%; n-butane, 2.58%; and others, 3.37%. The reaction temperature was 75°C, and the reaction time was 6 h. A maleic anhydride-C4 linear alternating copolymer (MC4L) with a number average molecular weight of 17000 g / mol was prepared for later use.

[0079] 2. The experimental data for the examples and comparative examples were determined using the following methods:

[0080] (1) Crystallization performance test: The PerkinElmer DSC8000 was used to test the sample, and the heating and cooling rates were 10℃ / min.

[0081] (2) Scanning Electron Microscopy (SEM): The sample was adhered to conductive adhesive, sputtered with gold, and then observed using a CoxEM EM-30 scanning electron microscope. The elemental composition and content were determined using the energy dispersive spectroscopy (EDS) spectrometer built into the SEM.

[0082] Example 1:

[0083] (1) Dissolve 20g of sodium hydroxide in 430g of water, then add 50g of MSL solid (number average molecular weight 42000g / mol) to form a homogeneous solution. Dry the solution in an oven at 95℃, grind it in a mortar and pestle to obtain powder with an average particle size of 250μm. The sodium element in the obtained maleic anhydride copolymer alkali metal modified product (MSL-Na) is 13% by weight.

[0084] (2) After mixing 5g of sodium hydroxide with 1000g of PET resin, the mixture was extruded and granulated in a twin-screw extruder. The resulting alkali metal modified PET (PET-Na) contained 0.28% sodium by weight.

[0085] (3) Take 0.25g of maleic anhydride copolymer alkali metal modified (MSL-Na) from step (1) and 11.5g of alkali metal modified PET (PET-Na) from step (2) and mix them evenly to obtain 11.75g ​​of compound nucleating agent for later use;

[0086] (4) 500g of PET resin and 11.75g ​​of compounding nucleating agent were mixed and extruded in a twin-screw extruder to obtain PET composition PET-1.

[0087] Comparative Example 1:

[0088] 500g of PET resin was extruded and granulated in a twin-screw extruder to obtain the PET composition PET-2.

[0089] Comparative Example 2:

[0090] (1) Dissolve 20g of sodium hydroxide in 430g of water, then add 50g of MSL solid (number average molecular weight 42000g / mol) to form a homogeneous solution. Dry the solution in an oven at 95℃, grind it in a mortar and pestle to obtain powder with an average particle size of 250μm. The sodium element in the obtained maleic anhydride copolymer alkali metal modified product (MSL-Na) is 13% by weight.

[0091] (2) 500g of PET resin was blended with 0.5g of maleic anhydride copolymer alkali metal modified (MSL-Na) from step (1), and extruded and granulated in a twin-screw extruder to obtain PET composition PET-3.

[0092] Comparative Example 3:

[0093] (1) After mixing 5g of sodium hydroxide with 1000g of PET resin, the mixture was extruded and granulated in a twin-screw extruder. The resulting alkali metal modified PET (PET-Na) contained 0.28g of sodium.

[0094] (2) 500g of PET resin was blended with 23g of alkali metal modified PET (PET-Na) from step (1), and extruded and granulated in a twin-screw extruder to obtain the PET composition PET-4.

[0095] Example 2:

[0096] (1) Dissolve 10g of sodium hydroxide in 268g of water, then add 50g of MSL solid (number average molecular weight 19800g / mol) to form a homogeneous solution. Dry the solution in an oven at 95℃, grind it in a mortar and pestle to obtain powder with an average particle size of 230μm. The sodium element weight in the obtained maleic anhydride copolymer alkali metal modified product (MSL-Na) is 6.5%.

[0097] (2) After mixing 3g of sodium hydroxide with 1000g of PET resin, the mixture was extruded and granulated in a twin-screw extruder. The resulting alkali metal modified PET (PET-Na) contained 0.15% sodium by weight.

[0098] (3) Take 0.75g of maleic anhydride copolymer alkali metal modified (MSL-Na) from step (1) and 25g of alkali metal modified PET (PET-Na) from step (2) and mix them evenly to obtain 25.75g of compound nucleating agent for later use;

[0099] (4) 500g of PET resin and 25.75g of compounding nucleating agent were mixed and extruded in a twin-screw extruder to obtain PET composition PET-5.

[0100] Example 3:

[0101] (1) Dissolve 15g of sodium hydroxide in 935g of water, then add 50g of MSL solid (number average molecular weight 23800g / mol) to form a homogeneous solution. Dry the solution in an oven at 95℃, grind it in a mortar and pestle to obtain powder with an average particle size of 235μm. The sodium element weight in the obtained maleic anhydride copolymer alkali metal modified product (MSL-Na) is 8.2%.

[0102] (2) After mixing 3g of sodium hydroxide with 1000g of PET resin, the mixture was extruded and granulated in a twin-screw extruder. The resulting alkali metal modified PET (PET-Na) contained 0.15% sodium by weight.

[0103] (3) Take 1.3g of maleic anhydride copolymer alkali metal modified (MSL-Na) from step (1) and 10g of alkali metal modified PET (PET-Na) from step (2) and mix them evenly to obtain 11.3g of compound nucleating agent for later use;

[0104] (4) 500g of PET resin and 11.3g of compounding nucleating agent were mixed and extruded in a twin-screw extruder to obtain PET composition PET-6.

[0105] Example 4:

[0106] (1) Dissolve 15g of sodium hydroxide in 935g of water, and weigh 50g of MSL (number-average molecular weight 23800g / mol) and add it to the sodium hydroxide aqueous solution. After forming a transparent solution (viscosity 34.5mPa·s), spray dry it, with the inlet air temperature at 180℃ and the outlet air temperature at 80℃. The collected powder of maleic anhydride copolymer alkali metal modified (MSL-Na) contains 8.3% sodium by weight, and its scanning electron microscope image is shown below. Figure 1 As shown, the average particle size of the maleic anhydride copolymer alkali metal modified product (MSL-Na) is 6.2 μm (average particle size measurement method: select 500 microspheres in the electron microscope image, measure their diameter, and calculate the average particle size of the microspheres by mathematical averaging).

[0107] (2) After mixing 3g of sodium hydroxide with 1000g of PET resin, the mixture was extruded and granulated in a twin-screw extruder. The resulting alkali metal modified PET (PET-Na) contained 0.15% sodium by weight.

[0108] (3) Take 1.3g of maleic anhydride copolymer alkali metal modified (MSL-Na) from step (1) and 10g of alkali metal modified PET (PET-Na) from step (2) and mix them evenly to obtain 11.3g of compound nucleating agent for later use;

[0109] (4) 500g of PET resin and 11.3g of compounding nucleating agent were mixed and extruded in a twin-screw extruder to obtain PET composition PET-7.

[0110] Example 5:

[0111] (1) Dissolve 20g of sodium hydroxide in 430g of water, then add 50g of MC4L (number average molecular weight 17000g / mol) solid to form a homogeneous solution. Dry the solution in an oven at 95℃, grind it in a mortar and pestle to obtain powder with an average particle size of 230μm. The sodium element in the obtained maleic anhydride copolymer alkali metal modified product (MC4L-Na) is 15% by weight.

[0112] (2) After mixing 5g of sodium hydroxide with 1000g of PET resin, the mixture was extruded and granulated in a twin-screw extruder. The resulting alkali metal modified PET (PET-Na) contained 0.28% sodium by weight.

[0113] (3) Take 0.25g of the maleic anhydride copolymer alkali metal modified (MC4L-Na) from step (1) and 11.5g of the alkali metal modified PET (PET-Na) from step (2) and mix them evenly to obtain 11.75g ​​of compound nucleating agent for later use;

[0114] (4) 500g of PET resin and 11.75g ​​of compounding nucleating agent were mixed and extruded in a twin-screw extruder to obtain PET composition PET-8.

[0115] Table 1 Crystallization properties of PET compositions

[0116] serial number Crystallization temperature / ℃ Crystallization half-width at half maximum (FWHM) / °C Cold crystallization temperature / ℃ PET-1 196.70 7.03 none PET-2 175.04 18.28 131.81 PET-3 189.66 14.94 none PET-4 194.78 9.56 129.94 PET-5 202.69 6.74 none PET-6 204.15 6.32 none PET-7 206.01 6.04 none PET-8 198.05 6.89 none

[0117] Table 1 shows that the data for PET-1 to PET-4 indicate that pure PET has a low crystallization temperature, a large half-width at half-maximum (HWHM), and exhibits cold crystallization, which greatly limits its application in heat-resistant fields. When maleic anhydride copolymer alkali metal modifier is introduced alone, the crystallization properties of PET are significantly improved, and cold crystallization is eliminated. When PET-Na masterbatch is introduced alone, the crystallization temperature and HWHM of PET are significantly improved, but cold crystallization still exists. When considering the same sodium element weight (the nucleating agent sodium content is the same for PET-1, PET-3, and PET-4), the improvement in crystallization properties after combining maleic anhydride copolymer alkali metal modifier with PET-Na is better than using either nucleating agent alone, and no cold crystallization occurs. The data for PET-6 and PET-7 further show that the product obtained by spray drying has a smaller particle size and does not agglomerate; the nucleation effect of using spray-dried maleic anhydride copolymer alkali metal modifier is better than that of oven drying.

Claims

1. A rapidly crystallizing PET composition comprising PET resin and a compounding nucleating agent; The compound nucleating agent comprises maleic anhydride copolymer alkali metal modified and alkali metal modified PET; The alkali metal modified maleic anhydride copolymer is obtained by combining alkali metal ions after ring opening of the maleic anhydride copolymer.

2. The rapidly crystallizing PET composition according to claim 1, characterized in that: The weight ratio of the PET resin to the compound nucleating agent is 100:(0.1-15), preferably 100:(0.2-10).

3. The rapidly crystallizing PET composition according to claim 1, characterized in that: The weight ratio of the maleic anhydride copolymer alkali metal modified product to the alkali metal modified PET is 1:(1-100), preferably 1:(1-50).

4. The rapidly crystallizing PET composition according to claim 1, characterized in that: The maleic anhydride copolymer used in the alkali metal modified maleic anhydride copolymer is preferably an alternating maleic anhydride copolymer, more preferably at least one of a linear alternating maleic anhydride copolymer, and even more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M is selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction, more preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

5. The rapidly crystallizing PET composition according to claim 1, characterized in that: The weight fraction of alkali metal elements in the maleic anhydride copolymer alkali metal modified product is 1%-22%, preferably 2%-20%.

6. The rapidly crystallizing PET composition according to claim 1, characterized in that: The morphology of the maleic anhydride copolymer alkali metal modified product is spherical or near-spherical, preferably with an average particle size of 2-15 μm, more preferably 4-10 μm.

7. The rapidly crystallizing PET composition according to claim 1, characterized in that: The structural features of the alkali metal modified PET are: PET reacts with alkali metal inorganic salts, and alkali metal ions are attached to the end groups of the PET molecular chain.

8. The rapidly crystallizing PET composition according to claim 1, characterized in that: The alkali metal modified PET contains 0.05%-1% by weight of alkali metal, preferably 0.05%-0.5%, and more preferably 0.05%-0.3%.

9. A method for preparing a rapidly crystallizing PET composition according to any one of claims 1 to 8, characterized in that... Includes the following steps: The components, including the compound nucleating agent and PET resin, are blended and processed to obtain the rapidly crystallizing PET composition.

10. The method for preparing the rapidly crystallizing PET composition according to claim 9, characterized in that... Includes the following steps: (1) Preparation of compound nucleating agent: Mix the components including maleic anhydride copolymer alkali metal modified and alkali metal modified PET to obtain compound nucleating agent; (2) After blending PET resin with a compound nucleating agent, the mixture is melt-processed to obtain the rapid crystallization PET composition.

11. The method for preparing the rapidly crystallizing PET composition according to claim 10, characterized in that: The preparation method of the maleic anhydride copolymer alkali metal modified material includes the following steps: An alkali metal inorganic salt was dissolved in water, and then a maleic anhydride copolymer was added. The mixture was reacted to obtain a solution, which was then dried to obtain an alkali metal modified maleic anhydride copolymer.

12. The method for preparing the rapidly crystallizing PET composition according to claim 10, characterized in that: The preparation method of the alkali metal modified PET includes the following steps: PET resin is melt-blended with alkali metal inorganic salt to obtain alkali metal modified PET; Preferably, the weight ratio of the PET resin to the alkali metal inorganic salt is 100:(0.05-15), and more preferably 100:(0.1-10).

13. The method for preparing the rapidly crystallizing PET composition according to claim 11 or 12, characterized in that: The alkali metal inorganic salt is selected from at least one of alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal sulfates, and alkali metal nitrates, preferably at least one of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, more preferably at least one of alkali metal hydroxides, and even more preferably sodium hydroxide.

14. The method for preparing the rapidly crystallizing PET composition according to claim 11, characterized in that: The maleic anhydride copolymer is preferably an alternating maleic anhydride copolymer, more preferably at least one of a linear alternating maleic anhydride copolymer, and even more preferably a linear alternating maleic anhydride copolymer obtained by combining structural unit A provided by maleic anhydride and structural unit B provided by monomer M; the monomer M is selected from monomers containing isolated carbon-carbon double bonds, preferably at least one of vinyl acetate, C4 olefin, C4 fraction, C5 olefin, C5 fraction, C8 olefin, C8 fraction, C9 olefin, and C9 fraction, more preferably at least one of vinyl acetate, styrene, α-methylstyrene, C4 olefin, C4 fraction, C5 olefin, and C5 fraction.

15. The method for preparing the rapidly crystallizing PET composition according to claim 11, characterized in that: The molar ratio of the maleic anhydride copolymer (calculated by anhydride groups) to the alkali metal inorganic salt (calculated by alkali metal elements) is 1:(0.1-4), preferably 1:(0.2-3).

16. The method for preparing the rapidly crystallizing PET composition according to claim 11, characterized in that: The amount of the maleic anhydride copolymer used is 0.1%-30% of the total weight of the solution, preferably 0.1%-15%, more preferably 0.1%-10%.

17. The method for preparing the rapidly crystallizing PET composition according to claim 11, characterized in that: The drying method is selected from at least one of vacuum drying, hot drying, freeze drying, and spray drying, preferably at least one of hot drying and spray drying, and more preferably spray drying; the temperature of the hot drying is preferably 75℃-150℃, and more preferably 80-95℃. Preferably, the inlet air temperature of the spray dryer is 150℃-200℃, more preferably 155℃-180℃; the outlet air temperature is 60℃-100℃, more preferably 70℃-95℃.

18. The method for preparing the rapidly crystallizing PET composition according to claim 17, characterized in that: The viscosity of the solution used for spray drying is less than 100 mPa·s, preferably less than 80 mPa·s, and more preferably less than 70 mPa·s.

19. The method for preparing the rapidly crystallizing PET composition according to claim 17, characterized in that: In the solution used for spray drying, the amount of maleic anhydride copolymer is 0.1%-15% of the total weight of the solution, preferably 0.1%-10%.

20. The method for preparing the rapidly crystallizing PET composition according to claim 11, characterized in that: The number-average molecular weight of the maleic anhydride copolymer is less than 30,000 g / mol, preferably less than 25,000 g / mol.

21. The PET composition product obtained by the preparation method according to any one of claims 9 to 20.

22. Application of the rapidly crystallizing PET composition according to any one of claims 1 to 8 or the PET composition obtained by the preparation method according to any one of claims 9 to 20, preferably in the field of injection molded products.

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