CN109337016B

CN109337016B - Process for controlling cross-linking side reaction generated in grafting reaction process

Info

Publication number: CN109337016B
Application number: CN201811187209.8A
Authority: CN
Inventors: 沈文祥
Original assignee: NANJING TANGCHENG PLASTIC CO Ltd
Current assignee: NANJING TANGCHENG PLASTIC CO Ltd
Priority date: 2018-10-12
Filing date: 2018-10-12
Publication date: 2021-04-06
Anticipated expiration: 2038-10-12
Also published as: CN109337016A

Abstract

The invention belongs to the technical field of high polymer materials, and relates to a process for controlling a crosslinking side reaction generated in a grafting reaction process, which is characterized in that the crosslinking side reaction generated in the melting grafting reaction process is controlled by adding auxiliary agents in sequence in the melting grafting reaction process, wherein the auxiliary agents comprise an initiator, a polar group and a crosslinking inhibitor. According to the invention, the cross-linking side reaction generated in the melt grafting reaction process is controlled by sequentially adding the initiator, the polar group and the cross-linking inhibitor, and the cross-linking side reaction is effectively controlled under the condition of improving the grafting rate. The maleic anhydride grafted polyethylene produced by the method has higher grafting rate, so that the application effect of the high polymer functional material is improved, and the application field is widened.

Description

Process for controlling cross-linking side reaction generated in grafting reaction process

Technical Field

The invention belongs to the field of high polymer materials, and relates to a preparation process for producing a high polymer functional material containing polar groups by an extrusion melting method grafting reaction.

Background

The polyolefin resin has excellent thermal property, mechanical property and processing property, so that the polyolefin resin is widely applied as a general resin. However, the non-polarity of polyolefin resins makes them poorly compatible with polar materials, resulting in poor adhesion, dyeability, hydrophilicity, and compatibility with organic and inorganic fillers, which limits the application of polyolefin resins. The polyolefin resin is functionally modified, so that the adhesive force, the compatibility and the dyeing property between the polyolefin resin and other high polymer materials can be improved, and the application range of the polyolefin resin is widened.

Graft modification of polyolefin is one of important means for functional modification of polyolefin resin. The melt grafting of polyethylene with maleic anhydride is a common method for improving the polarity of polyethylene, but the melt grafting method has the problem that the polyethylene can generate a crosslinking reaction under the action of maleic anhydride and peroxide, and the crosslinking reaction causes the viscosity of a system to be greatly increased, the flowing property to be poor and the extrusion to be difficult. Certain electron-rich additives or chain transfer agents have good inhibition on crosslinking reaction in the melt grafting process of maleic anhydride, thereby greatly reducing the gel content of the product.

Disclosure of Invention

The invention aims to control the cross-linking side reaction in the process of melt grafting reaction by adding an initiator, a polar group, an electron-rich additive or a chain transfer agent in a device for metering and adding an auxiliary agent according to the design requirement.

In order to achieve the above purpose: the branch art scheme of the invention is as follows: a process for controlling the cross-linking by-reaction generated in graft reaction features that the assistant including trigger, polar group and cross-linking inhibitor is sequentially added in the fusion graft reaction to control the cross-linking by-reaction generated in the fusion graft reaction.

Generally, the above-mentioned process for controlling the side reaction of crosslinking during the grafting reaction is to add the initiator, polar group and crosslinking inhibitor simultaneously in the order of the position of the metering device in the melt reaction section of the single-screw extrusion reaction plastic extruder.

And further, after the feeding plasticizing section is finished, sequentially and respectively arranging three metering devices at the second screw groove of the melting reaction section, arranging a second metering device at two screw grooves behind the first metering device, and arranging a third metering device at two screw grooves behind the second metering device.

Further, the initiator is dosed in a first dosing unit, the polar group is dosed in a second dosing unit, the crosslinking inhibitor is dosed in a third dosing unit, and the three dosing units are opened simultaneously.

The basic resin of the melt grafting reaction is polyolefin resin, and is selected from one or a combination of PE, POE and TPE resin.

The polar group is selected from one or a combination of more of maleic anhydride, acrylic acid, methacrylic acid and methyl acrylate.

The crosslinking inhibitor is an electron-rich additive or a chain transfer agent.

The initiator and the crosslinking inhibitor are commonly used in the field, for example, the initiator can be DCP (dicumyl peroxide), and the crosslinking inhibitor can be diphenyl phosphite.

The addition amount of the above-mentioned additives of the present invention is also well known in the art, and can be designed according to the actual needs.

In general, the polyolefin resin to be modified is first fed into a hopper of a single-screw extrusion reaction plastic extruder to be subjected to plasticizing extrusion. The initiator is added into the first metering device of the melting reaction section according to the formula design, the polar group is added into the second metering device according to the formula design, and the electron-rich additive or chain transfer agent is added into the third metering device according to the formula design, so that the purposes of improving the grafting rate and reducing or eliminating the cross-linking side reaction are achieved.

According to the invention, the auxiliary agent metering and adding device is adopted, the initiator, the polar group and the crosslinking inhibitor are added in sequence according to the design requirement, so that the crosslinking side reaction generated in the process of the melt grafting reaction is controlled, and the crosslinking side reaction is effectively controlled under the condition of improving the grafting rate. The maleic anhydride grafted polyethylene produced by the method has higher grafting rate, so that the application effect of the high polymer functional material is improved, and the application field is widened.

Detailed Description

The present invention will be described in detail with reference to examples.

Examples

The process of controlling the cross-linking side reaction in grafting reaction includes adding polyolefin resin to be modified into the hopper of single screw extruding reaction plastic extruder, and plasticizing and extruding.

In the embodiment, after the end of the feeding plasticizing section, three metering devices are respectively arranged in sequence from the second screw groove of the melting reaction section, the second metering device is arranged at the back of the first metering device by two screw grooves, and the third metering device is arranged at the back of the second metering device by two screw grooves.

Example the initiator was dosed in the first metering device, the polar group in the second metering device and the crosslinking inhibitor in the third metering device, the three metering devices being switched on simultaneously. And (3) performing reactive extrusion, bracing, cooling and granulating to prepare the high-molecular functional material.

Example (b): the formula of the maleic anhydride grafted polyethylene comprises the following components in percentage by weight:

LLDPE 100%；

DCP 0.8%；

1.5 percent of maleic anhydride;

1.0 percent of diphenyl phosphite.

Comparative example

Pouring polyolefin resin to be modified, an initiator, a polar group, an electron-rich additive or a chain transfer agent into a stirrer at the same time, fully and uniformly mixing, adding into a hopper of a single-screw extrusion reaction plastic extruder, and carrying out reaction extrusion, bracing, cooling and granulating to obtain the polyolefin resin.

Comparative example: the formula of the maleic anhydride grafted polyethylene comprises the following components in percentage by weight:

LLDPE 100%；

DCP 0.8%；

1.5 percent of maleic anhydride.

1.0 percent of diphenyl phosphite.

Comparison of data of experimental results of maleic anhydride grafted polyethylene

Description of the drawings: melt flow rate test standard: GB 3682;

grafting rate = [ M (V2-V1) × 98] × 100%/M (where M-molar concentration of oxalic acid, V2-volume consumed by oxalic acid solution calibration of 10 Mlkoh-ethanol solution, V1-volume consumed by oxalic acid solution titration of graft, M-mass of graft-purified);

gel content = (W3-W1) × 100%/(W2-W1) (where W1-mass of copper wire and packaging line, W2-mass of bale after sample loading, W3-mass of bale after extraction).

As can be seen from the comparison of the data of the above examples, the invention adopts the auxiliary agent metering and adding device, and the initiator, the polar group and the crosslinking inhibitor are added in the order of the design requirement to control the crosslinking side reaction in the process of the melt grafting reaction, thereby obtaining good effect and effectively controlling the crosslinking side reaction under the condition of improving the grafting rate. The maleic anhydride grafted polyethylene produced by the method has higher grafting rate, so that the application effect of the high polymer functional material is improved, and the application field is widened.

Claims

1. A process for controlling the generation of cross-linking side reaction in the process of grafting reaction is characterized in that the cross-linking side reaction generated in the process of melt grafting reaction is controlled by adding auxiliary agents in sequence in the process of melt grafting reaction, wherein the auxiliary agents comprise an initiator, a polar group and a cross-linking inhibitor; the method comprises the steps of simultaneously adding an initiator, a polar group and a crosslinking inhibitor into a melting reaction section of a single-screw extrusion reaction plastic extruder according to the position sequence of metering devices, namely after a feeding plasticizing section is finished, sequentially and respectively arranging three metering devices from a second screw groove of the melting reaction section, arranging a second metering device at two screw grooves behind the first metering device, arranging a third metering device at two screw grooves behind the second metering device, adding the initiator according to a formula in the first metering device, adding the polar group according to the formula in the second metering device, adding the crosslinking inhibitor according to the formula in the third metering device, and simultaneously opening the three metering devices.

2. The process for controlling the occurrence of side cross-linking reaction during grafting reaction as claimed in claim 1, wherein the base resin of the melt grafting reaction is polyolefin resin selected from one or more of PE, POE and TPE resin.

3. The process for controlling the generation of side cross-linking reactions during grafting according to claim 1 wherein the polar group is selected from the group consisting of maleic anhydride, acrylic acid, methacrylic acid, and methyl acrylate.

4. A process for controlling the occurrence of cross-linking side reactions during a grafting reaction as claimed in claim 1 wherein the cross-linking inhibitor is an electron rich additive or a chain transfer agent.