A low-temperature resistant modified PPR and its preparation process

Abstract

The present invention belongs to the technical field of PPR pipes, and specifically relates to a low-temperature resistant modified PPR. By weight, its raw materials include the following components: 80-100 parts of a modified PPR matrix, 0.5-3 parts of an antioxidant, 1-5 parts of a silane coupling agent, 10-20 parts of a filler, and 10-15 parts of a diluent. The modified PPR material prepared by the present invention has excellent low-temperature resistance and flame retardancy.

Description

Technical Field

[0001] The present invention belongs to the technical field of PPR pipes, and particularly relates to a low-temperature resistant modified PPR and its preparation process. Background Art

[0002] Polypropylene random copolymer, abbreviated as PPR, is a new type of plastic pipe product first developed and used in Europe and is the third-generation polypropylene product. Under the conditions of heating and pressurization, with the catalytic action of a catalyst, propylene monomers and a small amount of olefin monomers are randomly copolymerized. Due to the random introduction of ethylene molecules, this completely disrupts the arrangement and distribution of methyl groups on the tertiary carbon in the polymer molecular chain, thus hindering the formation of the crystalline state structure of the polymer and causing changes in the physical properties, mechanical properties, and crystallization properties of the random copolymer polypropylene.

[0003] Due to its excellent comprehensive properties, PPR has received increasing attention and is widely used in various industrial fields such as pipes, packaging bags, automotive components, and furniture. The PPR material has good heat resistance and pressure resistance, and good high-temperature creep performance. Compared with other plastics, it has great advantages in terms of environmental protection, recyclability, and the complexity of the processing technology. However, due to the low notched impact strength of PPR, especially its brittleness is particularly prominent at low temperatures (below 0°C) or high strain rates, and its impact performance and other aspects far fail to meet the technical requirements of various industrial fields, which to a certain extent limits its application scope. Therefore, effectively improving the low-temperature impact resistance of the PPR material has become a key technical problem to be solved urgently.

[0004] In addition, although PPR is a general-purpose thermoplastic resin and is widely used in all aspects of production and life due to its excellent comprehensive properties, PPR belongs to a flammable material, which greatly restricts its further application. Therefore, how to improve the flame retardancy of the PPR material is also a key technical problem to be solved urgently.

[0005] Based on this, there is an urgent need to develop a modified PPR material that simultaneously has low-temperature resistance and flame retardancy. Summary of the Invention

[0006] Aiming at the deficiencies in the prior art, the present invention aims to provide a low-temperature resistant modified PPR and its preparation process. To achieve the above object, the present invention adopts the following technical solutions:

[0007] A low-temperature resistant modified PPR, by weight, comprises the following raw materials:

[0008] Modified PPR matrix 80 - 100 parts

[0009] Antioxidant 0.5 - 3 parts

[0010] 1 - 5 parts of silane coupling agent

[0011] 10 - 20 parts of filler

[0012] 10 - 15 parts of diluent

[0013] The preparation method of the modified PPR matrix is as follows:

[0014] Add 50 - 80 parts of PPR matrix and 80 - 100 parts of acetone into a reactor, then add 3 - 5 parts of modifier and 1 - 3 parts of initiator, mix in a high - speed mixer for 10 - 20 min, and extrude through a twin - screw extruder to obtain the modified PPR matrix;

[0015] The structure of the modifier is: .

[0016] In some embodiments, the antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0017] In some embodiments, the coupling agent is selected from one or more of KH - 550, KH - 560, KH - 570, KH - 792, KH - 791, and DL - 602.

[0018] In some embodiments, the diluent is selected from one or more of ethylene glycol ethyl acetate, n - butyl glycidyl ether, diglycidyl ether, and 1,4 - butanediol diglycidyl ether.

[0019] In some embodiments, the filler is one or more of glass powder, mica powder, quartz powder, and asbestos powder.

[0020] In some embodiments, the initiator is selected from one or more of 1,1 - di - tert - butylperoxy - 3,3,5 - trimethylcyclohexane, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane, tert - butyl peroxycarbonate - 2 - ethylhexyl ester, and tert - butyl peroxycarbonate isopropyl ester.

[0021] In some embodiments, the preparation process of the low - temperature resistant modified PPR includes the following steps:

[0022] Mix the modified PPR matrix, antioxidant, silane coupling agent, filler, and diluent evenly according to the above weight parts to obtain a mixture; add the above mixture into a twin - screw extruder for melt extrusion, water cooling, and pelletizing to obtain pellets; put the pellets into an oven for drying and standby; inject - mold the dried pellets on an injection - molding machine to obtain the low - temperature resistant modified PPR.

[0023] In some embodiments, the extrusion process parameters are as follows: the extrusion temperatures are 190°C, 195°C, 200°C, 205°C, and 215°C respectively, and the main machine speed is 200 r / min.

[0024] In some embodiments, the injection molding process parameters are as follows: the injection molding temperatures are 230°C, 225°C, 220°C, 215°C, and 210°C respectively, and the injection molding pressures in zone 1, zone 2, zone 3, and zone 4 are 55 MPa, 50 MPa, 45 MPa, and 40 MPa respectively.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The modified PPR material prepared by the present invention has excellent low-temperature resistance and flame retardancy. On the one hand, the modifier of the present invention has a novel structure, and a siloxane flexible chain is introduced into its molecular structure, which can introduce soft and twistable segments into the PPR material, thereby improving the low-temperature resistance of the material; on the other hand, the modifier also introduces a triazine flame retardant group, and the flame retardant effect is excellent, so that the limiting oxygen index of the PPR material reaches 36.8, and the flame retardant grade of the horizontal and vertical burning test reaches V-0. Detailed implementation manners

[0027] The following non-limiting examples can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary illustration of the scope claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and it should also fall within the scope claimed by the present invention.

[0028] When the examples give a numerical range, it should be understood that unless otherwise specified in the present invention, any value at both ends of each numerical range and any value between the two ends can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0029] The present invention will be further described below by way of specific examples. All the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels unless otherwise specified.

[0030] Preparation Example 1 Preparation of the modifier

[0031] Step 1: Preparation of intermediate compound C

[0032] ;

[0033] Compound B (0.1 mol), compound A (0.12 mol), triethylamine (0.2 mol) and acetone (300 ml) were added to a three-necked flask. The reaction was stirred at 0 °C in a water bath for 4 h. After the reaction was completed, the resulting precipitate was filtered, and the precipitate was washed several times with acetone. The obtained solid was dried in an oven at 80 °C for 12 h to obtain the intermediate compound C as a white solid with a yield of 83.1%.

[0034] LC-MS (ESI): [M+H] + = 396.1

[0035] Step 2: Preparation of the modifier

[0036] ;

[0037] Under a nitrogen atmosphere, the intermediate compound C (0.1 mol), allylzinc chloride (0.25 mol), and Pd(PPh3)4 (0.01 mol) were added to a reactor, and then degassed THF (500 mL) was added. The temperature was raised to 50 °C and the reaction was stirred for 2 h. After the reaction was completed, the mixture was filtered, and the filtrate was washed 3 times with deionized water (300 mL x 3). The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was separated and purified by column chromatography to obtain the modifier compound with a yield of 90.2% and an HPLC purity of 99.4%.

[0038] LC-MS (ESI): [M+H] + = 408.2

[0039] 1 1H-NMR (500 MHz, CDCl3): δ (ppm): 5.41 - 5.35 (m, 2H), 5.11 - 5.03 (m, 4H), 3.61 (s, 9H), 3.50 - 3.42 (m, 4H), 3.35 - 3.22 (m, 8H), 2.30 - 2.21 (m, 2H), 1.52 - 1.41 (m, 2H), 0.58 - 0.50 (m, 2H).

[0040] Preparation Example 2 Preparation of the modifier PPR matrix

[0041] 80 parts of PPR matrix (RP2400, Hanwha Chemical Corporation) and 100 parts of acetone were added to the reactor, then 5 parts of the modifier obtained in Preparation Example 1 and 1 part of initiator 1,1 - di - tert - butylperoxide - 3,3,5 - trimethylcyclohexane were added, and they were mixed in a high - speed mixer for 10 min. Finally, the modified PPR matrix was obtained by extrusion with a twin - screw extruder. Among them, the extrusion process of the twin - screw extruder was: the first zone at 175 °C, the second zone at 180 °C, the third zone at 185 °C, the fourth zone at 190 °C, the fifth zone at 200 °C, the head temperature at 205 °C, the feeding frequency at 40 Hz, and the screw speed at 200 rpm.

[0042] Example 1

[0043] A low - temperature resistant modified PPR material, by weight, comprises the following raw materials:

[0044] 100 parts of modified PPR matrix

[0045] 1 part of antioxidant 1010

[0046] 3 parts of coupling agent KH - 560

[0047] 10 parts of filler mica powder

[0048] 15 parts of diluent diglycidyl ether

[0049] The preparation method of the above - mentioned low - temperature resistant modified PPR material is as follows:

[0050] Mix the modified PPR matrix, antioxidant, silane coupling agent, filler, and diluent evenly according to the above weight parts to obtain a mixture;

[0051] Add the above mixture to a twin - screw extruder for melt extrusion, water cooling, and pelletizing to obtain pellets. The extrusion process parameters are: extrusion temperatures of 190 °C, 195 °C, 200 °C, 205 °C, 215 °C, and the main machine speed of 200 r / min; dry the pellets in an oven at 90 °C for 3 h for standby. Inject the dried pellets on an injection molding machine to mold a standard sample of the low - temperature resistant modified PPR material. The injection molding process parameters are: injection temperatures of 230 °C, 225 °C, 220 °C, 215 °C, 210 °C, and injection pressures of 55 MPa in the first zone, 50 MPa in the second zone, 45 MPa in the third zone, and 40 MPa in the fourth zone.

[0052] Example 2

[0053] A low - temperature resistant modified PPR material, by weight, comprises the following raw materials:

[0054] 90 parts of modified PPR matrix

[0055] 2 parts of antioxidant 1076

[0056] 2 parts of coupling agent KH-570

[0057] 20 parts of filler quartz powder

[0058] 15 parts of diluent n-butyl glycidyl ether

[0059] The preparation method of the above low-temperature resistant modified PPR material is as follows:

[0060] Mix the modified PPR matrix, antioxidant, silane coupling agent, filler, and diluent evenly according to the above weight parts to obtain a mixture;

[0061] Add the above mixture to a twin-screw extruder for melt extrusion, water cooling, and pelletizing to obtain pellets. The extrusion process parameters are: extrusion temperatures of 190°C, 195°C, 200°C, 205°C, 215°C, and a main machine speed of 200 r / min; Dry the pellets in an oven at 90°C for 3 h for standby. Inject the dried pellets on an injection molding machine to form a standard sample bar of the low-temperature resistant modified PPR material. The injection molding process parameters are: injection temperatures of 230°C, 225°C, 220°C, 215°C, 210°C, and injection pressures of 55 MPa in zone 1, 50 MPa in zone 2, 45 MPa in zone 3, and 40 MPa in zone 4.

[0062] Example 3

[0063] A low-temperature resistant modified PPR material, by weight, includes the following raw materials:

[0064] 80 parts of modified PPR matrix

[0065] 1 part of antioxidant 1010

[0066] 2 parts of coupling agent DL-602

[0067] 15 parts of filler quartz powder

[0068] 10 parts of diluent 1,4-butanediol diglycidyl ether

[0069] The preparation method of the above low-temperature resistant modified PPR material is as follows:

[0070] Mix the modified PPR matrix, antioxidant, silane coupling agent, filler, and diluent evenly according to the above weight parts to obtain a mixture;

[0071] The above mixture was added to a twin-screw extruder for melt extrusion, water cooling, and pelletizing to obtain pellets. The extrusion process parameters were: extrusion temperatures of 190°C, 195°C, 200°C, 205°C, 215°C, and a main machine speed of 200 r / min. The pellets were dried in an oven at 90°C for 3 h for standby. The dried pellets were injection molded on an injection molding machine to obtain standard specimens of the low-temperature resistant modified PPR material. The injection molding process parameters were: injection temperatures of 230°C, 225°C, 220°C, 215°C, 210°C, and injection pressures of 55 MPa in zone 1, 50 MPa in zone 2, 45 MPa in zone 3, and 40 MPa in zone 4.

[0072] Comparative Example 1

[0073] On the basis of Example 1, the modified PPR matrix was replaced with an unmodified PPR matrix (RP2400, from Daehan Oil & Chemical Co., Ltd.). The specific method was as follows:

[0074] A low-temperature resistant modified PPR material, by weight, included the following raw materials:

[0075] 100 parts of PPR matrix

[0076] 1 part of antioxidant 1010

[0077] 3 parts of coupling agent KH-560

[0078] 10 parts of filler mica powder

[0079] 15 parts of diluent diglycidyl ether

[0080] The preparation method of the above low-temperature resistant modified PPR material was as follows:

[0081] The PPR matrix, antioxidant, silane coupling agent, filler, and diluent were mixed evenly according to the above weight parts to obtain a mixture;

[0082] The above mixture was added to a twin-screw extruder for melt extrusion, water cooling, and pelletizing to obtain pellets. The extrusion process parameters were: extrusion temperatures of 190°C, 195°C, 200°C, 205°C, 215°C, and a main machine speed of 200 r / min. The pellets were dried in an oven at 90°C for 3 h for standby. The dried pellets were injection molded on an injection molding machine to obtain standard specimens of the low-temperature resistant modified PPR material. The injection molding process parameters were: injection temperatures of 230°C, 225°C, 220°C, 215°C, 210°C, and injection pressures of 55 MPa in zone 1, 50 MPa in zone 2, 45 MPa in zone 3, and 40 MPa in zone 4.

[0083] Performance testing

[0084] To better reflect the performance of the low-temperature resistant modified PPR material of the present application, the low-temperature resistance and flame retardancy of the PPR materials prepared in Examples 1 to 3 and Comparative Example 1 were tested. The test methods are as follows:

[0085] 1) Tensile strength test: The test standard is ISO527 / 2-93;

[0086] 2) Low-temperature notch impact strength test: The test standard is ISO180-93;

[0087] 3) Limiting oxygen index (LOI) test: The test standard is GB / T 2406.2-2009;

[0088] 4) Vertical burning UL-94 test: The test standard is GB / T2408-2008.

[0089] The results are shown in Table 1.

[0090] Table 1 Performance test results

[0091]

[0092] From the data in Table 1, it can be seen that the modified PPR material prepared by the present invention has excellent low-temperature resistance and flame retardancy. The main reasons are as follows. On the one hand, the modifier of the present invention introduces a silicone oxygen alkane flexible chain, which can introduce soft and twistable segments into the PPR material, thereby improving the low-temperature resistance of the material; on the other hand, the modifier of the present invention introduces a triazine flame retardant group with excellent flame retardant effect, making the limiting oxygen index of the PPR material reach 36.8%, and the flame retardant grade of the horizontal and vertical burning test reach V-0.

[0093] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A low-temperature resistant modified PPR, characterized in that, by weight parts, It includes the following raw materials: 80 - 100 parts of modified PPR matrix, 0.5 - 3 parts of antioxidant, 1 - 5 parts of silane coupling agent, 10 - 20 parts of filler, 10 - 15 parts of diluent; The preparation method of the modified PPR matrix is as follows: Add 50 - 80 parts of PPR matrix and 80 - 100 parts of acetone into a reactor, then add 3 - 5 parts of modifier and 1 - 3 parts of initiator, mix in a high - speed mixer for 10 - 20 min, and extrude through a twin - screw extruder to obtain the modified PPR matrix; The structure of the modifier is as follows: .

2. The low-temperature resistant modified PPR according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

3. The low-temperature resistant modified PPR according to claim 1, wherein, The coupling agent is selected from one or more of KH - 550, KH - 560, KH - 570, KH - 792, KH - 791, and DL - 602.

4. The low-temperature resistant modified PPR according to claim 1, wherein The diluent is selected from one or more of n - butyl glycidyl ether, diglycidyl ether, and 1,4 - butanediol diglycidyl ether.

5. The low-temperature resistant modified PPR according to claim 1, characterized in that, The filler is one or more of glass powder, mica powder, quartz powder, and asbestos powder.

6. The low-temperature resistant modified PPR according to claim 1, wherein, The initiator is selected from one or more of 1,1 - di - tert - butylperoxy - 3,3,5 - trimethylcyclohexane, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane, tert - butyl peroxy - 2 - ethylhexyl carbonate, and tert - butyl peroxy isopropyl carbonate.

7. The preparation process of the low-temperature resistant modified PPR according to any one of claims 1-6, characterized in that, It includes the following steps: Mix the modified PPR matrix, antioxidant, silane coupling agent, filler, and diluent evenly according to the above weight parts to obtain a mixture; add the above mixture into a twin - screw extruder for melt extrusion, water cooling, and pelletizing to obtain pellets; put the pellets into an oven for drying and standby; inject - mold the dried pellets on an injection - molding machine to prepare the low - temperature - resistant modified PPR.

8. The preparation process according to claim 7, characterized in that, The extrusion process parameters are: the extrusion temperatures are 190°C, 195°C, 200°C, 205°C, 215°C respectively, and the main - machine speed is 200 r / min.

9. The preparation process according to claim 7, characterized in that, The injection - molding process parameters are: the injection - molding temperatures are 230°C, 225°C, 220°C, 215°C, 210°C respectively, and the injection - molding pressures in zone 1, zone 2, zone 3, and zone 4 are 55 MPa, 50 MPa, 45 MPa, and 40 MPa respectively.

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