DE3313442C2 - - Google Patents

Description

The invention relates to a polymer composition which

• (I) 5 to 95% by weight of a polyester with terephthalic acid as an acid component and 1 to 25 mol% of a glycol and 99 to 75 mol% tetramethylene glycol as Glycol component and
• (II) 95 to 5% by weight of a polycarbonate of a di (mono hydroxyphenyl) substituted aliphatic carbons hydrogen

contains.

The polytetramethylene terephthalate resin (hereinafter referred to as PBT resin) is a highly crystalline thermo plastic polyester resin and has an excellent Affinity for various fillers and additives. Because of this property, reinforced PBT resins have which are glass fibers, mica, talc and fire retardants added excellent properties. Example wise these resins are widely used in applications including electrical devices, electronic parts and automotive parts. In other words, possess PBT resins high mechanical strength, long life duration, weather resistance, chemical resistance, heat resistance, dimensional stability and electrical properties create. Polytetramethylene terephthalate resins have egg NEN higher degree of crystallization compared to poly ethylene terephthalate resins and have a higher crystal lization ratio. That is why the cooling process rate of flow is high and the fluidity is good, resulting in a  excellent resin formability results. The PBT resins are therefore engineering plastics with a gu balance between electrical and mechanical properties as well as the processing properties.

However, PBT resins have the following disadvantages:

• (1) PBT resins are inherently poor in di dimensional accuracy compared to non-crystalline plastics and plastics, which are difficult are to be crystallized. This difference will be particularly clearly under the influence of a temperature distribution in a metal mold. Subject to PBT resins also a shape shrinkage ratio, which depends on the thickness of the plastic. Is the cool speed is not constant, the shaped tends PBT product for the deformation and shrinkage of the Shape. This property increases the shrinkage aniso tropie of fiber orientation in with glass fibers strengthened PBT resins. The molded product tends to Deformation and creates the so-called fault.
• (2) Non-reinforced PBT resins lack plastics and are sensitive to notching. Around To overcome these drawbacks, various ge mixed resin compositions proposed. From be special interest is a combination of one PBT resin with a basically non-crystalline Resin, a polycarbonate resin. With this combination is the glass transition temperature of the polycarbonate 150 ° C increased and the impact resistance ver enlarged. Based on this finding, there are high Expectations of the mixed materials and it was actually mixed compositions with high thermal deformation temperatures and strengths obtained at high temperatures. The improvement visibly the impact resistance by combining the Resin with a polycarbonate was not enough pronounced and has none of the mixed materials, so  as far as impact resistance is concerned, the needs the user satisfactory. GB-14 96 018 describes also a mixture of a PBT resin, but ge may be modified, and a polycarbo natural resin. This mixture also shows no satisfaction properties.

The object of the present invention is a polymer composition with high thermal deformation temperature temperature and strength at high temperatures excellent anti-sag properties and high surface gloss to provide a modified poly ester resin is combined with a polycarbonate.

The object is achieved according to the invention by a polymer solved composition of the type mentioned, the is characterized in that in the polyester (I) condensed glycol 2-methyl-1,3-propylene glycol is.

The modified PBT resin used in the present invention is a polyester resin whose acid component is terephthal is acid and its glycol component from 1 to 25  Mol% 2-methyl-1,3-propylene glycol and 99 to 75 mol% Tetramethylene glycol exists.

The modified PBT resin according to the invention can, depending on following the procedure below will.

Basically, the mixed product is made by adding and / or to alone or, the resin composition consisting of PBT resin,  a resin composition consisting of a poly ester polymer obtained by polymerization reaction of terephthalic acid and 2-methyl-1,3-propanediol and a resin composition consisting of a Polyester copolymer obtained by a poly reaction of terephthalic acid and tetramethylene glycol and 2-methyl-1,3-propanediol.

The mixing method used can be chemical Process in which the starting materials in a Lö be solved, or a mechanical process, in the rolling, Banbury mixer, extruder or mold directions are used in a standard procedure, be.

For the preparation of the resin compositions, and  can the conventional method of producing Polyesters can be applied without further changes. This means that the resin compositions by the  direct process in which the dicarboxylic acid compound and the diol compound is directly polycondensed, or produced by the transesterification process can, in which the polycondensation by a Um esterification reaction between a low molecular weight term alkyl ester compound of a dicarboxylic acid compound with a diol.

The manufacture of a polyester copolymer Terephthalic acid and tetramethylene glycol as well as 2-methyl 1,3-propanediol is described below by way of example. One mole of dimethyl terephthalate and an excess of one or a 1.1 to 2.0 times molar total excess mixed diol of tetramethylene glycol and 2-methyl 1,3-propanediol undergoes a transesterification reaction in one Nitrogen flow using a standard esterification catalyst under normal pressure and at one temperature from about 150 to 240 ° C. The methanol produced is distilled off and the necessary amount of kata lysators, discoloration inhibitors and other additives the added. The reaction mixture is left a poly condensation at about 200 to 280 ° C under reduced Enter pressure less than 666.5 Pa (5 mm Hg). The one above put catalyst can from a wide range of ver bindings can be chosen. Examples of these are titanium compounds, such as tetramethoxytitanium, tetraethoxytitanium, Tetra-n-propoxytitanium, tetraisopropoxytitanium and tetra butoxytitanium, tin compounds, such as di-n-butyltin dilau rat, di-n-butyltin oxide and dibutyltin diacetate and Combinations of the acetic acid salts of magnesium, calcium or zinc with antimony oxide or those listed first Titanium compounds. These catalysts are in the range from 0.002 to 0.8% by weight, based on the total amount posed copolymer, used. Discoloration inhibitors, which are phosphorus-containing compounds, such as phosphorus Acid, phosphoric acid, trimethyl phosphite, tridecyl phosphite, triphenyl phosphite, trimethyl phosphate, tridecyl  phosphate and triphenyl phosphate are effective. It's be prefers such discoloration inhibitor in the range of 0.001 to 0.3 wt .-%, based on the total, formed Copolymer to use.

The poly-2-methyl substituted 1,3-propylene terephthalate Component consisting of terephthalic acid and 2-methyl-1,3- propylene glycol, as part of the modi according to the invention Fected polybutylene terephthalate resin (I) is in one Amount of 1 to 25 mol%, preferably 1 to 20 mol%, based on the total polymer (I) included. Is that Amount of poly-2-methyl substituted 1,3-propylene tereph thalate component less than 1 mole%, the mixture with regard to plasticity and shape shrinkage not ver improves. The amount of this component is more than 25 mol% are in the resulting PBT resin Melting point and the degree of crystallization decreased, whereby the thermal and mechanical strength is reduced will. For this reason, the resin is difficult with that Mix polycarbonate (II) because the resin and the poly carbonate in terms of thermal behavior from each other are too different.

The modified polyester used in the present invention Resin (I) is made using terephthalate acid, 2-methyl-1,3-propylene glycol and tetramethylene glycol as raw materials. However, it is also possible Lich to use other copolymer components, such as tetravalent aliphatic carboxylic acids, such as adipic acid, Azelinic acid and sebacic acid, polyvalent aromatic Carboxylic acids, such as isophthalic acid, trimellitic acid, Pyromellitic acid and 2,6-naphthalenedicarboxylic acid and Polyols, such as ethylene glycol, propylene glycol, 1,6-hexanediol, 1,4-dichlorohexane diol, cyclohexane dimethanol, trimethylol propane and pentaerythritol, each in suitable amounts depending on the desired goals.  

The polycarbonate resin (II) used according to the invention is a polycarbonate of di- (monohydroxyphenyl) -substi tuated aliphatic hydrocarbons. In particular it is a bisphenol polycarbonate, being 4,4'-dihydroxy diphenylalkane polycarbonate is particularly preferred. The most preferred example is the polycarbonate of bisphenol A (4,4'-dihydroxy-2,2'-diphenylpropane).

The polycarbonate (II) preferably has one mole eyepiece weight of approximately 30,000 or over 30,000.

It is possible to put together into the polymer according to the invention setting suitable amounts of additives known per se to incorporate, depending on the composition desired properties and effects. For example lubricants such as an organic acid amide, Wax, crystallization nuclei, oxidation inhibitors, Ultraviolet ray absorbing agents, inhibitors for static electricity and fire retardants, be added.

The polymer composition according to the invention can also about 5 to 40% by weight, preferably 10 to 30% by weight, organic or inorganic fibers or particles as contain reinforcing fillers. From the fillers glass fibers are particularly preferred, the total importance of this filler in the range specified above should be. It was known to improve mechani properties of the resins and especially Er increase the impact resistance of polyesters, such as Use PBT resins, glass fibers. The addition of glass fibers to a composition according to the invention shows even a greater impact than predictable and that Impact resistance is increased far more than expected. The amount of the composition according to the invention added set glass fibers can therefore be lower than normal, with the desired effect still being realized  becomes.

The composition according to the invention contains 5 to 95 % By weight, preferably 20 to 80% by weight, of the polycarbonate and 95 to 5% by weight, preferably 80 to 20% by weight, of the modified PBT resin. Is the amount of ver If polycarbonate is used less than 5% by weight, the Impact resistance of the mixed composition is not improved. If this amount exceeds 95% by weight, the melt flow property of the resin be disadvantageous influences. In the manufacture of the invention Polymer composition can include both components a temperature above the melting point of each polymer are mixed, with the preferred temperature range is between 150 and 300 ° C. The mixing process can be a chemical process in which the components in one Solvents are mixed and mixed or a mechanical process using rollers, Bunbury Mixers, extruders or molding devices. In each In this case, the normally used procedure or the equipment is used.

Although the reason that the present invention is a resin composition with outstanding impact resistance is not fully clarified, the following can Theory.

The PBT resins generally have a low impact strength because they are resins with high crystallinity. On the other hand, the polycarbonate resins generally have mean excellent impact resistance since they Polymers with a low degree of crystallinity. A simple mixture of a PBT resin and a polycarbo However, natural resin does not result in improvement of the blow strength to the extent expected. This disappointing The result was attributed to the fact that the sol  parameters for the PBT resin 10.8 and for the Polycarbonate resin amount to 9.8. The difference of the sol of 1.0 and the fact that the PBT Resin is a highly crystalline polymer and the polycarbonate resin is a relatively non-crystalline polymer as the cause of the low mutual solubility see. That is, the mixed resin consisting of one PBT resin and a polycarbonate resin contains a PBT phase, an area where both resins are mutually interlocking are solved and a polycarbonate phase. These phases exist relatively independently of each other, so this as the cause of the value of the impact resistance, which under remains what is expected.

In contrast to this, the modified PBT resin a glycol component, which again sweeping units or part of the tetramethylene glycol which is the linear glycol component which partly by 2-methyl-1,3-propylene glycol substi which is a glycol component with a be represents chain. The presence of the side chain under breaks the regularity of the polymer chain and reduces corresponding to the degree of crystallinity.

The modified PBT resin according to the invention thus has a much larger amount of non-crystalline phase and is considered the cause, a polymer together clogging with a surprisingly high impact resistance result if suitably with a polycarbonate resin is mixed.

The following examples illustrate the invention. In the examples, the term "parts" refers to "Parts by weight". The properties of the resins were determined by following procedures determined.

(1) Poly-2-methyl-1,3-propylene terephthalate content

Contents of poly-2-methyl-1,3-propylene terephthalate, as indicated in Table 1 below, be calculates as mol% using the nuclear magnetic re resonance spectra (NMR).

(2) intrinsic viscosity

The intrinsic viscosity was at 25 ° C in o-chlorine phenol determined.

(3) Melting point and heat of fusion

The differential scanning calorific was used for this measurement meters used by Perkin Elmer, model DSC-1B. As The heat of fusion for Sn was used as standard.

(4) Relative degree of crystallinity

It was the peak area based on the melting of the resin as obtained with a differential ab tactile calorimeter, used. The peak area of PBT (Resin 1 in Table 1) the value of 100% was added wrote.

(5) Tensile strength limit and elongation at break

It became the Tensilon UTM-1-5000 B device from the company Toyo Baldwin Co. used in accordance with the procedure described in ASTM D-638.

(6) Izod impact test

It became the company's Izod impact tester Toyo Seiki Seisakushyo Co. used. For the notched Testing was the procedure described in ASTM-D-256 applied.  

(7) Thermal deformation temperature

It became the procedure described in ASTM D-648 used with a load of 181.8 N / cm² (18.56 kg / cm²).

Production Example 1

The PBT resin was made according to that described below Process manufactured.

A mixture of 194.0 parts of dimethylerephthalate, 135.0 parts tetramethylene glycol and 0.20 parts titanium Tetrabutoxide catalyst was placed in a reactor brings that with a twin-screw stirrer was equipped of the tape type. The implementation became one Hour at 180 ° C in a stream of nitrogen and under Normal pressure continued. After that, the reaction mixture heated to 230 ° C over 2.5 hours and that generated methanol distilled off, 90% of theories table quantity were achieved. Thereafter, 0.02 parts Tridecylphosphit added to the reaction mixture and the Temperature of the reaction mixture increased to 250 ° C. The Pressure within the reaction system was over 40 min. reduced to 26.7 Pa (0.2 mm Hg) and the polymerization Continued 3.5 h under these conditions.

Production Example 2

The modified PBT resin was made according to the following described method produced.

A mixture of 194.0 parts of dimethyl terephthalate, 121.5 parts tetramethylene glycol and 2-methyl-1,3-propane diol and 0.20 parts of titanium tetrabutoxide catalyst placed in a reactor with a double screw-type stirrer of the belt type was equipped.  

The reaction was carried out in a stick at 180 ° C. for 1 h material flow and continued under normal pressure. The reaction The mixture was then heated to 230 ° C. for 2.5 h 90% of the theoretical amount of methanol produced were distilled. Thereafter, 0.02 part of tridecyl phosphite added to the reaction mixture and the tempera tur of the reaction mixture increased to 250 ° C. The pressure of the Reaction system was raised to 26.7 Pa (0.2 mm Hg) over 40 min. reduced and the polymerization 3.5 h among them Conditions continued.

Production Examples 3 and 4

The modified PBT resins were made from different Shares in tetramethylene glycol and 2-methyl-1,3-propane diol as listed in Table 1 below Application of that described in Production Example 2 Process manufactured.

The properties of the in the production examples 1 to 4 polymers and copolymers obtained are shown in Table 1 listed.  

Table 1

Examples 1, 2 and 3 and Comparative Examples 1 and 2

The polyesters and bisphenol A polycarbonate obtained in the preparation examples were air-dried at 60 ° C. for 8 hours. The dried polymers were mixed together in the proportions listed in Table 2 below, and 0.4 part of tridecyl phosphite was added to these mixtures. The mixtures were kneaded and extruded into pellets using an extruder equipped with a mono-axial full-flight type screw with an inner diameter of 40 mm and kept at 230 to 250 ° C. The pellets obtained were air dried at 80 ° C for 8 hours and molded into test specimens using a standard injection molding machine at 52 ° C. The properties of the compositions obtained are listed in Table 2 below. The properties of the above-described polycarbonate and the polyester (PBT resin) obtained in Production Example 1 are shown as Reference Examples 1 and 2.

The aim of the present invention is one Improvement of a mixed polymer composition made of polybutylene glycol and one defined as (II) Polycarbonate. This is achieved by using the Glycol component 2-methyl-1,3-propanediol, the one Has alkyl group in the 2-position. The previously known Mixture of polybutylene glycol and polycarbonate (II), Listed as Comparative Example 1 is regarding the thermal deformation temperature and the bending strength or stiffness at high temperature ver improves compared to polybutylene glycol alone, However, is not in the impact resistance desired extent improved. The present invention solves this problem and creates a blend of poly butylene glycol and the polycarbonate (II) with unexpected improved impact resistance while the high values regarding the thermal deformation temperature and the tensile strength limit are maintained. From the The above results show that the composition according to the invention a mixture with expedient properties that out in all respects are billowing. Since it is required that the mixture has a high thermal deformation temperature, is the mixture of Comparative Example 2, the one thermal deformation temperature is too low, not suitable.

Claims (1)

Polymer composition containing

• (I) 5 to 95% by weight of a polyester with terephthalic acid as the acid component and 1 to 25 mol% of a glycol and 99 to 75 mol% of tetramethylene glycol as the glycol component and
• (II) 95 to 5 wt .-% of a polycarbonate of a di (mono hydroxyphenyl) -substituted, aliphatic hydrocarbon, characterized in that the glycol condensed into the polyester (I) is 2-methyl-1,3-propylene glycol.