POLYFORMALDEHYDE COMPOSITE MATERIAL AND PREPARATION METHOD THEREOF

Abstract

The present invention provides a polyformaldehyde composite material, in parts by weight, including the following components: 70 to 95 parts of a polyformaldehyde; 5 to 20 parts of a SEBS; wherein, the SEBS is acid modified or amine modified. Due to modification by acid or amine, and presence of a polystyrene segment, a compatibility of the SEBS with the polyformaldehyde reduces because of a steric hindrance effect, which reduces an ability of a POM molecular chain to arrange regularly. When injection molded into a product or template, an incompatibility of the material itself will form a micro-rough effect on a surface of the material. When an incident light reaches the micro-rough surface, a reflection direction of the light will change and thus a diffuse reflection occurs, and a low-gloss material is obtained.

Claims

1. A polyformaldehyde composite material, in parts by weight, comprising the following components: 70 to 95 parts of a polyformaldehyde; and 5 to 20 parts of a SEBS (styrene ethylene butylene styrene); wherein, the SEBS is acid modified or amine modified.

2. The polyformaldehyde composite material according to claim 1, wherein the acid modified SEBS contains a carboxylic acid functional group; and the amine modified SEBS contains an amino group.

3. The polyformaldehyde composite material according to claim 2, wherein the SEBS has an acid value of 5 to 15 (mg CH.sub.3ONa/g).

4. The polyformaldehyde composite material according to claim 1, wherein the acid modified SEBS is prepared by performing an acid modification, which adopts a bromination method or an acetylation method, a bromine group or an acetyl group is attached to a para position of a benzene ring, and then an acidification is performed by acid or the acetyl group is oxidized to obtain a carboxylic acid functional group; and wherein the amine modified SEBS is prepared by performing an amine modification, which introduces a nitro group to the para position of the benzene ring in the SEBS, and then the nitro group is converted into an amino group through a reduction reaction.

5. The polyformaldehyde composite material according to claim 4, wherein the SEBS is grafted with GMA (glycidyl methacrylate) first, and then the acid modification is performed on the GMA branch.

6. The polyformaldehyde composite material according to claim 1, wherein a weight average molecular weight of the SEBS is 30000 to 100000, wherein a styrene segment accounts for 10% to 40% of a total segment molecular weight.

7. The polyformaldehyde composite material according to claim 1, wherein the polyformaldehyde is at least one of homopolyformaldehyde or copolyformaldehyde; a melting index of the polyformaldehyde is (2 to 28) g/10 min, wherein a temperature is 190° C. and a weight is 2.16 KG when measuring the melting index of the polyformaldehyde.

8. The polyformaldehyde composite material according to claim 1, in parts by weight, further comprising 0.5 to 1.2 parts of a formaldehyde absorbent; the formaldehyde absorbent is selected from at least one of magnesium oxide, magnesium hydroxide, aluminum oxide and aluminum hydroxide.

9. The polyformaldehyde composite material according to claim 1, in parts by weight, further comprising 0.1 to 10 parts of an auxiliary agent; the auxiliary agent is selected from at least one of an antioxidant, a lubricant, a heat stabilizer, and an UV absorbing additive.

10. A preparation method of the polyformaldehyde composite material according to claim 9, comprising the following steps: adding the polyformaldehyde, the SEBS, and the auxiliary agent into a high-speed mixer to mix uniformly, and then extruding and granulating by a screw to obtain the polyformaldehyde composite material; wherein, the screw has a temperature of 120 to 200° C., and a rotation speed of 250 to 500 rpm.

11. (canceled)

12. The polyformaldehyde composite material according to claim 1, wherein the SEBS is amine modified.

13. The polyformaldehyde composite material according to claim 2, wherein a weight average molecular weight of the SEBS is 30000 to 100000, wherein a styrene segment accounts for 10% to 40% of a total segment molecular weight.

14. The polyformaldehyde composite material according to claim 3, wherein a weight average molecular weight of the SEBS is 30000 to 100000, wherein a styrene segment accounts for 10% to 40% of a total segment molecular weight.

Description

DESCRIPTION OF THE EMBODIMENTS

[0037] The present invention will be further explained by specific implementations below. The following embodiments are implementations of the present invention that better embody the idea of the invention, but the implementations of the present invention are not limited by the following embodiments.

[0038] Raw materials used in experiments of embodiments and comparative examples are the following raw materials, but are not limited to the following raw materials:

[0039] Polyformaldehyde: Longyu POM MC90, copolymerized POM, with a melt index: 9 g/10 min (190° C./2.16 KG);

[0040] SEBS-A: acid modified, SEBS raw material being Kraton G1650, self-made modified by applying an acid modification method in a manual, with an acid value of 10.2 mg CH.sub.3ONa/g, a weight average molecular weight of about 70,000, and a styrene segment content of about 30%;

[0041] SEBS-B: amine modified, SEBS raw material being Kraton G1652, self-made modified by applying an amine modification method in a manual, with an acid value of 5.1 mg CH.sub.3ONa/g, a weight average molecular weight of about 50000, and a styrene segment content of about 30%;

[0042] SEBS-C: ordinary SEBS, SEBS 3151, without an acid modification or amine modification, with a molecular weight of about 40,000, and a styrene segment content of about 32%;

[0043] SEBS-D: 5902, with a GMA grafting rate of 3%, without acid modification or amine modification;

[0044] SEBS-E: acid modified, GMA grafted SEBS, self-made modified by applying an acid modification method in a manual, with an acid value of 9.7 mg CH.sub.3ONa/g, a weight average molecular weight of about 65000, and a styrene segment content of about 27%;

[0045] Magnesium oxide: KYOWAMAG 150; Antioxidant: hindered phenolic antioxidant IRGANOX 245/hindered phenolic antioxidant RIANOX 1098.

[0046] A preparation method of a polyformaldehyde composite material of the embodiments and the comparative examples includes the following steps: adding the polyformaldehyde, the SEBS, an auxiliary agent and a formaldehyde absorbent into a high-speed mixer to mix uniformly, and then extruding and granulating through a screw to obtain the polyformaldehyde composite material; wherein, the screw has a temperature of 120/160/170/180/180/180/180/180/180/190° C., and a rotation speed of 300 rpm.

[0047] Each Performance Test Method:

[0048] (1) Gloss: a gloss degree is tested by a photoelectric gloss meter. 10 pieces of 100 mm*100 mm*2.0 mm square plates each were injection molded, the photoelectric gloss meter (60° angle) was used to test the gloss of 10 square plates, and an average was taken.

TABLE-US-00001 TABLE 1 A ratio (parts by weight) of each component and each performance test results for the embodiments and the comparative examples Embodiment Embodiment Embodiment Embodiment Embodiment 1 2 3 4 5 Polyformaldehyde 85 85 85 85 85 SEBS-A 5 8 12 20 — SEBS-B — — — — 12 SEBS-C — — — — — SEBS-D — — — — — SEBS-E — — — — Magnesium oxide 0.8 0.8 0.8 0.8 0.8 Antioxidant 0.3 0.3 0.3 0.3 0.3 Gloss 26.2 21.5 16.8 4.3 11.3 Embodiment Comparative Comparative Comparative 6 Example 1 Example 2 Example 3 Polyformaldehyde 85 85 85 85 SEBS-A — — — — SEBS-B — — — — SEBS-C — 12 — — SEBS-D — — 12 — SEBS-E 12 — — — Magnesium oxide 0.8 0.8 0.8 0.8 Antioxidant 0.3 0.3 0.3 0.3 Gloss 19.7 75.2 69.8 86.5

[0049] It can be seen from Embodiments 1 to 4 and Comparative Example 3 that as an addition amount of acid modified SEBS increases, the gloss of a surface of the polyformaldehyde composite material decreases.

[0050] It can be seen from Embodiment 3 or 5 and Comparative Example 1 or 2 or 3 that ordinary SEBS cannot effectively reduce the surface gloss of the polyformaldehyde composite material.

[0051] It can be seen from Embodiment 3 and Embodiment 5 that the amine modified SEBS has a better delustering effect.