WO2016106837A1

WO2016106837A1 - Reactive thermoplastic resin composition and manufacturing method thereof

Info

Publication number: WO2016106837A1
Application number: PCT/CN2015/070579
Authority: WO
Inventors: 单桂芳; 李强; 罗明华; 辛敏琦
Original assignee: 上海锦湖日丽塑料有限公司
Priority date: 2014-12-31
Filing date: 2015-01-13
Publication date: 2016-07-07
Also published as: CN104559114A

Abstract

A reactive thermoplastic resin composition, comprising the following components in portion by mass: 15-85 portions of polycarbonate resin; 15-85 portions of polybutylene terephthalate resin; 0.05-5 portions of ester exchange inhibitor; 0-30 portions of impact modifier; 0-5 portions of additive; the polybutylene terephthalate has an intrinsic viscosity of 0.6-1.5 dl/gr and an end-COOH content of < 50 meq/kg. The present invention, by designing components of the composition, then combining optimization of an extrusion process and controlling the degree of transesterification, constructs a special micro-phase structure, and the obtained resin composition has an excellent stiffness and modulus under a quasi-static state and exhibits an excellent toughness and energy absorption property when subject to a high speed surface impact at a low temperature.

Description

Reactive thermoplastic resin composition and preparation method thereof

Technical field

The invention relates to a reactive thermoplastic resin composition and a preparation method thereof, and belongs to the technical field of polymer material processing.

Background technique

In recent years, in the field of automotive parts and sporting goods, there has been an increasing demand for energy absorption capacity when materials are subjected to high-speed impact. For example, the head impact test on the surface of the dashboard of the car; the knee impact test on the lower edge; the body impact test of the seat back, etc., all require that the interior plastic to be inspected cannot be broken, and the debris cannot be broken or edged. Injury. Automotive exterior trim must meet pedestrian safety standards. In addition, due to the needs of its own use environment, the toughness damage requirements of the car when it is impacted in a low temperature environment are becoming more and more urgent.

Currently, materials used to prepare energy absorbing components are mainly concentrated in rubber toughening systems and PC/PBT systems. For example, CN101558121 discloses that a polyamide elastomer resin composition having a polyamide 6 and a reactive functional group is prepared by using a twin-screw extruder having a ratio of length to diameter (L/D) of more than 50, and the prepared resin composition is microscopically prepared. The phase behavior is as follows: the nano-scale dispersed polyolefin elastomer contains a large number of smaller nano-scale polyamide 6 micelles, and exhibits remarkable excellent energy absorption properties at the macroscopic level, but its bending mode at room temperature. The amount is only 1300 MPa; for the PC/PBT system, Chinese patents CN 103772934A and CN 101935446A both disclose the interface of the obtained PC/PBT resin composition by adding a functionalized elastomer together with an interface compatibilizer and a toughening agent. The high-strength, high-notch impact performance is excellent; and the two-phase continuous structure having a structural period of 0.001 to 1 μm or 0.01 to 1 μm is constructed by a spinodal phase separation mechanism, as disclosed in US Pat. No. 7,523,612 and Japanese Patent No. 2003-286414. Excellent heat resistance and tensile properties.

As mentioned above, the disadvantage of the rubber toughening system is that it has low rigidity and heat resistance at room temperature, and is not suitable for use as a structural member, and the introduction of a large amount of rubber components may cause difficulty in processability and thermal stability. A series of problems for balance; for the PC/PBT system, it is mainly concentrated in three aspects: (1) pay attention to the impact performance of the gap, and pay little attention to the surface impact performance; (2) focus on how to construct the double continuous using the Spinodal phase separation mechanism. Phase structure; (3) Pay attention to the phase interface strength of PC and PBT.

Summary of the invention

In view of the deficiencies in the prior art, an object of the present invention is to provide a reactive thermoplastic resin composition and Preparation.

The object of the invention is achieved by the following technical solutions:

The present invention relates to a reactive thermoplastic resin composition comprising the following components in parts by weight:

Wherein, the polybutylene terephthalate has an intrinsic viscosity of 0.6 to 1.5 dl/gr and a terminal-COOH content of <50 meq/kg.

One of PC or PBT forms a continuous phase, and the other forms a dispersed phase, and the dispersed phase has a particle size of 0.05 to 0.5 μm or an interparticle distance of 0.05 to 0.5 μm; preferably, the dispersed phase has a particle size of 0.05 to 0.2 μm. Or the distance between particles is 0.05 to 0.2 μm.

Preferably, the polycarbonate resin is a bisphenol A type polycarbonate having a weight average molecular weight of 2.0 to 6.0 × 10 ⁴ g/mol.

Preferably, the polybutylene terephthalate has an intrinsic viscosity of 1.0 to 1.3 dl/gr and a terminal-COOH content of <10 meq/kg.

Preferably, the transesterification inhibitor is one of a phosphate and a phosphite.

Preferably, the impact modifier is a rubber-modified styrene resin, and examples thereof include an MBS resin (methyl methacrylate-butadiene rubber-styrene copolymer) and an ABS resin (acrylonitrile-butyl). Diene rubber-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), AES resin (acrylonitrile-ethylene propylene rubber-styrene copolymer) and HIPS (high impact polystyrene) Wait.

Preferably, the auxiliary agent comprises at least one of a stabilizer, a colorant, an antistatic agent, a plasticizer, and a lubricant.

The present invention also relates to a method for producing a thermoplastic resin composition according to the present invention, which comprises using a polycarbonate resin, a polybutylene terephthalate resin and an auxiliary agent in a double length to diameter ratio of 50 or less. The screw extruder is melt-kneaded to control the temperature at which the polymer melt exits the twin-screw extruder die to be less than 320 °C.

As a preferred method, the twin-screw extruder has an aspect ratio of not more than 35, and controls the temperature at which the polymer melt exits the twin-screw extruder die to be less than 300 °C.

The inventors of this patent have undergone extensive experiments and have surprisingly discovered that by adding transesterification inhibitors and controlling PBT The end-COOH content, while controlling the aspect ratio of the screw and the melt temperature, that is, simultaneously controlling the reaction time and the reaction temperature, can control the degree of transesterification of PC and PBT during the melt-kneading process, thereby controlling the embedding process generated by the transesterification process. The content of the segment copolyester can further control the separation speed of spinodal phase. The final construction of a large number of nanometer-scale dispersed dispersed phase-continuous phase structure can greatly improve the high-speed surface impact performance of PC/PBT system at low temperature.

Based on the above principle, the present invention firstly reduces the transesterification reaction in the PC and PBT resin compositions by controlling the content of the transesterification inhibitor and the content of the end-COOH in the PBT from the material properties; and in combination with the extrusion process (screw length) Optimization of ratio and melt temperature further control reaction time and reaction temperature; thereby reducing the content of PC-PBT block copolyester, accelerating the separation speed of spinodal phase, and constructing a dispersed phase-continuous phase with a large number of nanoscale dispersions The structure ultimately achieves the macroscopic properties of the composition, especially the high-speed surface impact performance at low temperatures. It was found by transmission electron microscopy that, with the resin composition prepared by the present invention, the dispersed phase can absorb a large amount of impact energy by forming a sponge-like multiple void structure when subjected to high-speed surface impact at a low temperature. That is, the resin composition prepared by the present invention exhibits excellent rigidity and heat resistance at normal temperature, and exhibits toughness damage after penetrating the hammer at a low temperature subjected to high load and high speed surface impact, and does not generate more than 10 mm. The above cracks.

Compared with the prior art, the present invention has the following beneficial effects:

Firstly, by designing the material composition properties, combined with the optimization of the extrusion process, controlling the degree of transesterification reaction, a special microscopic phase structure can be constructed, and the obtained resin composition has excellent rigidity and modulus, and is subjected to high load at low temperature. When the surface is impacted at a high speed, the toughness can be broken after the hammer is penetrated, and cracks larger than 10 mm or more are not generated. It was found by transmission electron microscopy that, with the resin composition prepared by the present invention, the dispersed phase can absorb a large amount of impact energy by forming a sponge-like multiple void structure when impacted at a low temperature and high speed surface.

DRAWINGS

Other features, objects, and advantages of the present invention will become apparent from the Detailed Description of Description

Figure 1 is a TEM photograph of a product of Example 1 of the present invention;

2 is a TEM photograph of the product of Comparative Example 1 of the present invention.

detailed description

The invention will now be described in detail in connection with specific embodiments. The following examples are intended to further understand the invention, but are not intended to limit the invention in any way. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the inventive concept. These are all within the scope of protection of the present invention.

The thermoplastic resin composition of the present invention is a resin composition of polycarbonate and polybutylene terephthalate, which is heat The plastic polyester is easily transesterified directly during the melt-kneading process to produce a block copolyester. Copolyesters act as compatibilizers for PC and PBT alloys, so much research has focused on how to accelerate or even accelerate the transesterification reaction to enhance the phase interfacial strength of PC and PBT and improve the performance of the resin composition. In fact, the inventors of this patent have found through extensive experiments that the presence of block copolyesters affects the phase separation rate of PC and PBT, and the content of block copolyesters can be controlled by controlling the degree of transesterification. The phase separation speed of PC and PBT constructs a dispersed phase-continuous phase structure with a large number of nanoscale dispersions. When the dispersed phase is uniformly dispersed in the continuous phase at the nanometer scale (10-500 nm), and the inter-particle distance of the dispersed phase is on the nanometer scale (10-500 nm), the nano-scale dispersed phase spacing makes the stress fields on the dispersed phase mutually Superposition forms macroscopic stresses of the resin composition in whole or in part, and this stress field superposition effect is more intense at low temperatures. Stress-induced voiding can occur when the number of dispersed phases dispersed at the nanometer scale is further increased or by further reducing the phase domain size of the dispersed phase to increase the number of dispersed phases dispersed at the nanometer scale. When subjected to high-speed impact in a low temperature environment, the continuous phase first undergoes shear deformation, and then a tensile stress is applied to the dispersed phase to cause multiple voiding of the dispersed phase to produce a sponge-like structure and absorb a large amount of energy. The resin composition exhibits excellent surface impact properties at a low temperature and high speed.

Therefore, how to control the transesterification reaction to a reasonable level is the key to affect the high-speed surface impact performance of PC and PBT at low temperatures. First, in terms of raw materials, the Ti catalyst remaining in the PBT synthesis process accelerates the transesterification reaction, and the addition of phosphate or phosphite can form a complex with the catalyst, which effectively inhibits the transesterification reaction; secondly, the extrusion process In terms of reaction time and reaction temperature, it is an important condition affecting the transesterification reaction, wherein the reaction time is controlled by the aspect ratio of the screw, and the reaction temperature is controlled by the melt temperature. Note that the melt temperature is two concepts with the barrel temperature of the extruder. The melt temperature of the extruder is determined by the barrel temperature of the extruder and the shear heat generation inside the extruder, while the shear heat generation accounts for most of the proportion; It is closely related to screw combination, screw speed, specific torque, barrel temperature and so on.

In order to obtain a resin composition having a specific structural period as described above, it is preferred to form a structure by spinodal spinodal separation. Compatibilization is preferably carried out by melt-kneading using a strong shear field using a twin-screw extruder.

The products obtained in each of the examples and the comparative examples were prepared into a sample of 100 mm × 100 mm × 3 mm in the performance test, and then tested according to ASTM D3763, the diameter of the hammer head was 12.7 mm, and the diameter of the bottom support ring was 76 mm, the test temperature. It is -40 ° C and the test speed is 20 m / s.

Examples 1 to 4

The raw materials used are:

The weight average molecular weight of the polycarbonate is 35,000;

Polybutylene terephthalate (PBT1) has an intrinsic viscosity of 1.0 dl/g and a terminal-COOH content of 20 meq/kg;

The transesterification inhibitor is sodium dihydrogen phosphate;

The impact modifier was an MBS resin (methyl methacrylate-butadiene rubber-styrene copolymer) having a particle diameter of 300 nm.

Each component was taken in parts by weight as shown in Table 1, and then the thermoplastic resin composition was prepared by the following method:

Step 1, weighing each component by weight;

Step 2, the components are thoroughly mixed in a high speed mixer for 20 min to obtain a mixture;

Step 3, the mixture is introduced from the main feed of the twin-screw extruder, and melt-extruded, cooled, dried, and pelletized to obtain the thermoplastic resin composition; the screw diameter of the twin-screw extruder is 30 mm. The aspect ratio is 32, and the melt temperature is controlled to be 280 to 300 °C.

A TEM photograph of the product of Example 1 is shown in Figure 1. As shown in Fig. 1, a large amount of PBT is uniformly dispersed in PC in a particle size of about 100 to 150 nm, and the pitch of PBT particles is 100 to 300 nm.

Comparative Example 1 to 5

In order to better embody the above characteristics for the thermoplastic resin composition, Comparative Examples 1 to 5 were used herein. Comparative Example 1 is the effect of the end-COOH content of PBT. The intrinsic viscosity of PBT (PBT2) is 1.0 dl/g and the end-COOH content is 60 meq/kg; Comparative Example 2 is the effect of transesterification inhibitor; Comparative Example 3 is Effect of screw length to diameter ratio (reaction time); Comparative Example 4 is the influence of melt temperature (reaction temperature); Comparative Example 5 is the influence of microscopic phase structure (co-continuous phase). The weight ratio of the raw materials is shown in Table 1, and the preparation methods are the same as those in Examples 1 to 4.

A TEM photograph of the product of Comparative Example 1 is shown in Fig. 2. As shown in Fig. 2, a large amount of PBT is uniformly dispersed in the PC at a particle size of about 1.0 to 1.5 μm to form a bicontinuous phase structure.

As shown in Table 1, a total of 9 formulations were melt extruded, pellet cooled, and granulated according to the above preparation method to prepare a thermoplastic resin composition, and the material was dried at 80 ° C for 12 h to ensure the water absorption of the resin before injection molding was <0.05%. The physical properties of the respective resin compositions were then tested by injection molding into splines under the same injection molding conditions in accordance with ASTM standards. Among them, the tensile strength and elongation were measured according to the test procedure of ASTM D-638, and the tensile speed was 50 mm/min; the flexural strength and the flexural modulus were measured according to the test procedure of ASTM D-790, and the loading speed was 3 mm/min; based on ASTM The D-256 test procedure measures Izod (1/8") notched impact strength at -30 ° C; the heat distortion temperature is determined based on the ASTM D-648 test procedure.

A molded article having a length of 100 mm x a width of 100 mm and a thickness of 3 mm was prepared by injection molding, and the surface impact property was measured based on the test degree of ASTM D-3763, the ambient temperature was -40 ° C, and the impact speed was 20 m / s. The crack fracture length after the penetration of the hammer body was measured, and the fracture length was determined to be a ductile fracture with a fracture length of less than 10 mm, and a brittle fracture was determined to be greater than 10 mm.

It can be seen from the experimental results of Examples 1 to 4 that the thermoplastic resin composition prepared according to the present invention has Excellent mechanical and thermal properties, and exhibits excellent low temperature impact properties and surface impact properties at low temperatures and high speeds, manifesting as toughness damage.

Compared with Comparative Examples 1 to 2, changing the composition properties and content of the resin composition can significantly change the microscopic phase structure. Comparative Example 1 is to change the content of -COOH in the middle of PBT, and Comparative Example 2 is to change the content of transesterification inhibitor, which obviously changes the microscopic phase structure, so that the size of the dispersed phase domain becomes larger, and the impact performance of low-temperature high-speed surface changes. Poor, the composition exhibits brittle failure.

Compared with Comparative Examples 3 to 4, the phase structure of the resin composition was changed by changing the extrusion process (the aspect ratio of the twin-screw extruder and the melt temperature) to form a homogeneous structure (microphase scale < 50 nm), the low-temperature impact and surface impact properties of the resin composition were also significantly reduced, and the heat resistance was drastically lowered.

Compared with Comparative Example 5, by simultaneously changing the group distribution ratio and the extrusion process to form a periodic co-continuous phase structure, the resulting low-temperature impact and surface impact properties of the resin composition are also not as the dispersed phase mentioned in the present invention - Continuous phase structure.

Table 1

In summary, the invention firstly constructs a special large amount of nanometer-scale dispersed dispersed phase-continuous phase microscopic phase structure through the material component attribute design and the optimization of the extrusion process, and the obtained resin composition has excellent performance. The rigidity and modulus, while subjected to high-load, high-speed surface impact at low temperatures, can exhibit toughness damage after penetrating the hammer, and do not produce cracks greater than 10 mm. It was found by transmission electron microscopy that, with the resin composition prepared by the present invention, the dispersed phase can absorb a large amount of impact energy by forming a sponge-like multiple void structure when impacted at a low temperature and high speed surface. That is, the resin composition prepared by the present invention exhibits excellent rigidity and heat resistance at normal temperature, and exhibits toughness damage after penetrating the hammer at a low temperature subjected to high load and high speed surface impact.

The specific embodiments of the present invention have been described above. It is to be understood that the invention is not limited to the specific embodiments described above, and various modifications and changes may be made by those skilled in the art without departing from the scope of the invention.

Claims

A reactive thermoplastic resin composition characterized by comprising the following components in parts by weight:

Wherein, the polybutylene terephthalate has an intrinsic viscosity of 0.6 to 1.5 dl/gr and a terminal-COOH content of <50 meq/kg.
The reaction type thermoplastic resin composition according to claim 1, wherein the polycarbonate resin is a bisphenol A type polycarbonate having a weight average molecular weight of 2.0 to 6.0 × 10 4 g/mol.
The reactive thermoplastic resin composition according to claim 1, wherein the polybutylene terephthalate has an intrinsic viscosity of 1.0 to 1.3 dl/gr and a terminal-COOH content of <10 meq/kg.
The reactive thermoplastic resin composition according to claim 1, wherein the transesterification inhibitor is one of a phosphate and a phosphite.
The thermoplastic resin composition according to claim 1, wherein the auxiliary agent comprises at least one of a stabilizer, a colorant, an antistatic agent, a plasticizer, and a lubricant.
A method for producing a thermoplastic resin composition according to claim 1, wherein the polycarbonate resin, the polybutylene terephthalate resin, and the auxiliary agent are doubled having an aspect ratio of 50 or less. The screw extruder is melt-kneaded to control the temperature at which the polymer melt exits the twin-screw extruder die to be less than 320 °C.