CN1034179C - Process for preparation of polyethylene glycol terephthalate engineering plastics - Google Patents

Abstract

The present invention relates to a preparation method for PRT engineering plastics. The components of the PRT engineering plastics comprise PET resin, glass fibers, a nucleating agent and a nucleation accelerating agent, and the components are together blended, extruded and pelletized by a double-screw extruder. The nucleation accelerating agent adopts a compound of which the structure is disclosed in the specification, and also performs the function of an antioxidant. If the nucleating agent adopts an ionic polymer, the reduction of PET molecular weight is less under the condition of higher cross blend extrusion temperature and longer screw detention time. PET engineering plastics prepared by the preparation method have the advantages of higher Izod impact strength and better color.

Description

The preparation method of polyethylene terephthalate plastics

The present invention relates to a kind of preparation method of polyethylene terephthalate (PET) plastics.

PET is the macromolecular material of excellent property, is mainly used in the production of fiber and film at present.Because the crystallization velocity of PET is very slow, second-order transition temperature is higher, and its molding processability can be relatively poor, and the mechanical property of moulded parts is also very poor, has run into certain difficulty as plastics.

Supreme Being people company had at first developed glass fibre enhanced PET plastics in 1966, but mold temperature is up to more than 130 ℃.E.I.Du Pont Company had successfully developed easy crystal type PET plastics in 1980, added nucleator and nucleation accelerating agent in PET, mold temperature more than 90 ℃, be lower than 120 ℃, and beginning suitability for industrialized production.The mechanical property of PET plastics, electrical property, thermal characteristics and solvent resistance are all fine, use also very extensively, can be used for electronic component, electrical component, machinery, automobile component etc., and cheap.So many companies competitively research and develop the PET plastics, seek novel nucleator and nucleation accelerating agent, in the hope of further some rerum natura that reduces mold temperature or improve the PET plastics.

The objective of the invention is to improve the crystallization velocity in the PET plastics preparation process, reduce the mould temperature, reduce and add component, the PET plastics that processability is good.

The component of PET plastics comprises PET resin, glass fibre, nucleator and nucleation accelerating agent, and they are through super-dry, mixing, extrude with glass fibre blend in twin screw extruder.Nucleation accelerating agent is that structure is

Compound, R wherein ₁Be the group that contains C, H, O, C atom number can be from 1～21, and O atom number can be from 0～2, R ₂And R ₃Can be H or CH ₃Or C (CH ₃) ₃

The consumption of PET resin, nucleator, nucleation accelerating agent, glass fibre is respectively (Wt%): 35～78%, 20～40%, 1～15%, 1～10%.

The PET resin is the resin that is used for producd fibers, or the high molecular weight resin that obtains of solid state polymerization, and its limiting viscosity [η] is between 0.5～10, and limiting viscosity [η] is more higher good, and molecular weight and molecular weight is few.The PET resin also can comprise a spot of comonomer, for example glycol ether.Glass fibre is that plastics strengthen universal non-alkali glass macrofiber, and coupling agent treatment is used on the surface, for example uses silane treatment, and its diameter is 5～15 μ n.

Nucleation accelerating agent is that structure is

Compound, R wherein ₁Be the group that contains C, H, O, the number of C atom can be from 1～21, and O atom number can be from 0～2, R ₂And R ₃Can be H or CH ₃Or C (CH ₃) ₃They can be 2,6 ditertiary butyl p cresol or β-positive octadecanol ester of (4-hydroxyl-3,5-di-tert-butyl-phenyl) propionic acid.This nucleation accelerating agent not only has good promoter action to the crystallization of PET, also has anti-oxidant cracked effect, reduces the degraded of PET under the high temperature.

Nucleator can be the ionic polymer that contains carboxylic acid sodium salt, its main chain can be the multipolymer of ethene and methacrylic acid or acrylic acid multipolymer, vinylbenzene and acrylic acid multipolymer and vinylbenzene and maleic anhydride, and the hydroxy-acid group of ionic polymer has at least 30% to be neutralized salify.Ionic polymer is preferably selected the ethylene-methacrylic acid copolymer that contains carboxylic acid sodium salt for use, the Surlyn 1601 of E.I.Du Pont Company for example, with this nucleator and

The PET plastics performance of the nucleation accelerating agent system preparation of structure is more good.

Only used three kinds of additives in the preparation process, promptly except the PET resin, also had glass fibre, nucleator, nucleation accelerating agent, the weight percent of their consumption is respectively: 35～78%, 20～40%, 1～15%, 1～10%.Nucleation accelerating agent had both promoted crystallization, had antioxidant effect again, and the general additive of its amount ratio is higher slightly good, and nucleator and nucleation accelerating agent consumption can not be too low, too low amazing effect.

PET resin, nucleator, the necessary thorough drying of nucleation accelerating agent after thorough mixing is even, are extruded with the blend in twin screw extruder of exsiccant glass fibre again.

Extrude with glass fibre blend in twin screw extruder through super-dry, well-mixed PET resin, nucleator, nucleation accelerating agent.Blending condition in the twin screw is a rotating speed: 120～250 rev/mins, and extruder temperature: in 190～290 ℃ of scopes.If adopting ionic polymer is nucleator, nucleator and nucleation accelerating agent can be made master batch in advance, and master batch and PET thorough mixing are even, after the drying, extrude with the glass fibre blend.When adopting ionic polymer Surlyn 1601 to be nucleator, higher extrusion temperature and long screw rod residence time, the PET molecular weight reduces still less.

Blended product obtains the PET plastics through pelletizing, after the thorough drying, prepares the Mechanics Performance Testing batten by U.S. ASTM standard, and molding temperature is 90 ℃, and carries out Mechanics Performance Testing by U.S. ASTM standard.

Additive to the testing method of the influence of PET crystallization behavior is: the section part of batten sampling 5～15mg measures with Dupont 1909B thermal analyzer one DSC after Mechanics Performance Testing, 10 ℃/min of heat-up rate records second-order transition temperature Tg, intensification crystallization peak-to-peak temperature T _Ch, the intensification peak crystallization crystallization enthalpy Δ H _Ch, fusing point T _mLower the temperature immediately after being warming up to 300 ℃, 10 ℃/mm of cooling rate records decrease temperature crystalline peak-to-peak temperature T _CcCrystallization enthalpy Δ H with the decrease temperature crystalline peak _CcTg, T _ChReduce many more, the expression nucleation accelerating agent effect good more, T _CcRaising more, multilist shows that the effect of nucleator is good more.Can adopt Δ H _Ch/ Δ H _CcOr Δ T=T _Cc-T _ChEstimate total effect of nucleator/nucleation accelerating agent system, Δ H _Ch/ Δ H _CcPreferably less than 0.2, Δ T is more preferably greater than 90 ℃.

The measuring method of molecular weight is: adopting phenol/tetrachloroethane (weight ratio 1: 1) is solvent, and about/100 milliliters of strength of solution C=0.5 grams are at 25.0 ± 0.1 ℃ of relative viscosity η that survey PET with Ubbelohde viscometer _r(η _r=t/t., t and t.Be respectively the elution time of solution and solvent), by point formula: $\left[\mathrm{\η}\right]=\frac{\sqrt{1+1.4(\mathrm{\ηr}-1)}-1}{0.7C}$ Obtain limiting viscosity [η], again by [η]=2.1 * 10 ^-4M η ^0.82Calculate viscosity-average molecular weight M η.

The present invention forms simply, four kinds of components only, and raw material is common to be easy to get.Adopt

Be nucleation accelerating agent, can not only promote the crystallization of PET, also have anti-oxidant cracked effect concurrently.Adopting ionic polymer such as Surlyn1601 is nucleator, not only can improve crystallization velocity, and is detained molecular weight and molecular weight that the long time makes PET on the contrary still less when higher extruder temperature.This nucleator/nucleation accelerating agent system has overcome the major defect that nucleator in the past, nucleation accelerating agent cause the PET molecular weight sharply to descend in the blend process.The good mechanical performance of PET plastics of the present invention, shock strength have surpassed existing like product, and have more weak color and better gloss.

Embodiment 1:

10KgPET ([η]=0.8), 80 ℃ of dryings are 4 hours in convection oven, 120～130 ℃ of dryings 8～10 hours.The 1Kg ionic polymer be Surlyn1601 of E.I.Du Pont Company and 0.4Kg 2,6 ditertiary butyl p cresol (

) at room temperature dry more than 72 hours in vacuum drying oven.Then joining again in the hopper of twin screw behind their abundant mixings.Twin screw is introduced on dry limit, the KH-560 glass fibre of Yaohua Glass-making Plant, Shanghai limit in 100 ℃ baking oven.It is 30% of total amount that the control feed rate makes content of glass fiber.Screw speed: 200 rev/mins, moment of torsion about 60, the screw zones temperature is as follows:

Back segment	The stage casing	Leading portion	Melt temperature
				240～260℃	250～260℃	270～280℃	275～285℃

After blend is extruded, through water cooling pelletizing again.Pellet in convection oven 80 ℃ dry 4～6 hours down.On the BOY-50N of BOY company type injection moulding machine, prepare batten, 90 ℃ of mould temperature, 7 seconds inject time, 8 seconds dwell times, injection pressure: 3.92～4.41MPa.The performance of embodiment 1 sees Table 1.

Table 1. embodiment 1 compares with du pont company like product performance

	Embodiment 1	Rynite FR530		Rynite 530
					The parallel laboratory test value	Literature value	Literature value
		Tg(℃) T ch(℃) T cc(℃) T m(℃) ΔH ch/ΔH ccIzod notched Izod impact strength (J/m) tensile break strength (MPa) extension at break (%) mould temperature (℃)	85.6 107.3 218.7 253.7 0.098 124 128 2.5 90	65.2 102.8 218.6 255.0 0.053 74.8 133 1.6 90				------------85.4 152 2.3 95～120 mold surface temperatures	------------101 158 2.7 95～120 mold surface temperatures

Embodiment 2:

According to the operating method of embodiment 1, with following formulation PET plastics:

PET([η]＝0.7)： 10Kg

Surlyn1650： 0.7Kg

P ^*： 0.4Kg

Glass fibre: 3.33Kg* P is β-positive octadecanol ester of (4-hydroxyl-3,5-di-tert-butyl-phenyl) propionic acid Relevant performance data is as follows:

Izod notched Izod impact strength (J/m)	Tensile break strength (MPa)	ΔH ch/ΔH cc
			93.3	132	0.152

Comparative example:

According to the operating method of embodiment 1, with following formulation PET plastics

PET： 10Kg

Surlyn1601： 1Kg

PEO (polyethylene oxide): 0.3Kg

The relevant performance data of glass fibre: 3.39Kg is as follows:

Tg(℃)	T ch(℃)	T cc(℃)	T m(℃)	ΔH chΔH cc	Izod notched Izod impact strength (J/m)	Tensile break strength (MPa)
							63.2	100.0	224.2	254.4	0.098	59.2	54.2

Embodiment 3:

According to the ratio of 5% (weight ratio), select for use appropriate solvent to dissolve various nucleation accelerating agents respectively, add the PET powder then, this suspension constantly stirs to remove under infrared lamp and desolvates, and oven dry is dry more than 72 hours in 50 ℃ of vacuum drying ovens again.Table 2 is that various PET/ nucleation accelerating agent samples are in the molecular weight determination result of 300 ℃ of thermal treatments after 3 minutes.Can find

To the minimum that influences of PET molecular weight, from 2.2 * 10 ⁴Drop to 2.1 * 10 ⁴

Many kinds of nucleation accelerating agents of table 2 are to the influence of PET molecular weight

Annotate: the PEO polyethylene oxide

P100 one condensed ethandiol benzoic ether

The Ph-phenyl

Claims (3)

1. the preparation method of a polyethylene terephthalate (PET) plastics, it is that PET resin, nucleator and nucleation accelerating agent are through super-dry, mixing, extrude with glass fibre blend in twin screw extruder, it is characterized in that: (1) nucleation accelerating agent is that structure is Compound, R wherein ₁Be the group that contains C, H, O, C atom number can be from 1～21, and O atom number can be from 0～2, R ₂And R ₃Can be H or CH ₃Or C (CH ₃) ₃(2) consumption of PET resin, nucleator, nucleation accelerating agent, glass fibre is (Wt%):

Polyethylene terephthalate (PET): 35～78%

Glass fibre: 20～40%

Nucleator: 1～15%

Nucleation accelerating agent: 1～10%

2. the preparation method of polyethylene terephthalate according to claim 1 (PET) plastics is characterized in that nucleator and nucleation accelerating agent can be that ionic polymer and the structure that contains carboxylic acid sodium salt is

The compound system.

3. the preparation method of polyethylene terephthalate plastics according to claim 1 is characterized in that twin screw blend extrusion temperature is 190～290 ℃, and screw speed is 120～250 rev/mins.