JPH07247348A - Modified polyester - Google Patents

Abstract

(57) [Summary] [Structure] The main constituent component is an aromatic dicarboxylic acid residue, an alkylene glycol residue, and a soft segment, and the ratio of the amount of the soft segment to polyester is 5 to 40% by weight, and A modified polyester characterized by satisfying the following two conditions. (1) Tg <55 ° C. (2) 500 ≦ MV ≦ 4000 (poise) (In the formula, Tg is the glass transition point of polyester and MV is the melt viscosity of polyester at 280 ° C.) [Effect] Excellent color tone It is possible to obtain a polyester, a film, a sheet and other molded products having pinhole resistance, heat resistance, impact resistance, and moldability such as film formation, and particularly suitable as a packaging film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flexible molded article, and more particularly to a modified polyester capable of forming a film. More specifically, the present invention relates to a modified polyester which has excellent pinhole resistance, heat resistance and impact resistance, and which can easily form a flexible molded product having a good color tone.

[0002]

2. Description of the Related Art Polyesters, particularly polyethylene terephthalate and polyesters containing them as a main component, have excellent physical and chemical properties and are widely used as fibers, films and molded articles.

However, it lacks flexibility, impact resistance, and adhesiveness at room temperature or low temperature, and cannot be applied especially to applications requiring pinhole resistance such as packaging films.
In order to improve such a defect, a method of copolymerizing a polyester with a soft segment has been considered. For example, JP-B-42-8709 discloses a copolymer of aromatic dicarboxylic acid polymethylene glycol with a dimerized fatty acid, and JP-B-54-19893 discloses polyethylene terephthalate and / or polytetramethylene terephthalate with a long chain. Copolymers of aliphatic dicarboxylic acids, and Japanese Patent Publication Nos. 1-16412 and 2-25377 disclose polyethylene terephthalate copolymerized with aliphatic dicarboxylic acids.

[0004]

However, aromatic dicarboxylic acid polymethylene glycol ester copolymerized with dimerized fatty acid, and polyethylene terephthalate and / or polytetramethylene terephthalate copolymerized with long-chain aliphatic dicarboxylic acid. Since the amount of the copolymerized dimerized fatty acid is large, it becomes a very viscous polymer, which makes it difficult to handle as a film. The polyethylene terephthalate copolymerized with an aliphatic dicarboxylic acid achieves the flexibility and pinhole resistance required by the present invention by judging from the copolymerization amount in the Examples or the Young's modulus of the film. There were drawbacks such as being unable to do so.

The object of the present invention is to eliminate the above-mentioned conventional drawbacks, and is excellent in pinhole resistance, heat resistance, impact resistance, and excellent in moldability such as extrusion molding such as film formation, and good. Another object of the present invention is to provide a flexible molded product showing various color tones, particularly a modified polyester capable of easily forming a film.

[0006]

Means for Solving the Problems The above-described object of the present invention is based on polyester having a soft segment as a main constituent, a polyester composed of an aromatic dicarboxylic acid residue and an alkylene glycol residue, and a polyester having a soft segment amount. It can be achieved by a modified polyester characterized in that the ratio is 5 to 40% by weight and the following two conditions are satisfied. (1) Tg <55 ° C. (2) 500 ≦ MV ≦ 4000 (poise) (In the formula, Tg is the glass transition point of the polyester, and MV is the melt viscosity of the polyester at 280 ° C.)

In the present invention, the polyester means a hard segment mainly containing an aromatic dicarboxylic acid residue as an acid component, and a soft segment mainly containing a dimerized fatty acid residue and a polyether residue, It is composed of an alkylene glycol residue as a glycol component.

In the present invention, the aromatic dicarboxylic acid residue constituting the hard segment is formed from an aromatic dicarboxylic acid and its ester-forming derivative. Specific examples include the following.

[Chemical 1] (X in the formula is -O-, -SO-, -SO _2- , -C (CH ₃ ) _2- ,
-CO-, n is 0 or 1. Further, the hydrogen atom bonded to the aromatic ring may be substituted with a halogen group. In the present invention, examples of the acid component that constitutes the aromatic dicarboxylic acid residue include the following.

[Chemical 2] (Wherein R _{1 to} R ₆ are hydrogen atoms or alkyl groups, and X is
_{-O-, -SO-, -SO 2 -,} -C (CH 3) 2 -, -CO-, n is 0
Or 1. Further, the hydrogen atom bonded to the aromatic ring may be substituted with a halogen group. ) Specifically, terephthalic acid, isophthalic acid, phthalic acid,
Examples thereof include naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid, benzophenonedicarboxylic acid, and ester-forming derivatives thereof. Among them, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid,
And ester-forming derivatives thereof are preferred. These aromatic dicarboxylic acid components may be used alone or in combination of two or more.

In the present invention, the amount of the aromatic dicarboxylic acid residue is preferably 80 to 99 mol% of the acid component, more preferably 83 to 95 mol%, further preferably 85 to 93 mol%. is there. When the amount of the aromatic dicarboxylic acid residue is less than 80 mol%, the heat resistance of the polyester may be lowered and the mechanical properties of a molded product obtained from the polyester may be lowered. On the other hand, if it exceeds 99 mol%, the flexibility of the molded product may decrease.

In the present invention, the soft segment is mainly composed of a dimerized fatty acid residue and a polyether.

In the present invention, the dimerized fatty acid residue means
It is formed from a dicarboxylic acid obtained by dimerizing an unsaturated fatty acid, and specifically has 10 carbon atoms represented by the following formula.
Examples thereof include dimerized fatty acids obtained by dimerizing 30 to 30 unsaturated fatty acids or ester-forming derivatives thereof.

CH ₃ (CH ₂ ) _K (CH = CH-CH ₂ ) _l (CH ₂ )
_m COOR (wherein R is a hydrogen atom or an alkyl group, k is 1 to 2)
5 is an integer, 1 is an integer of 1 to 5, m is an integer of 0 to 25,
k, l and m satisfy the following relational expression. 8 ≦ k + 3l + m ≦ 28)

In the dimerization reaction of this unsaturated fatty acid,
Monomers, trimers and the like are formed together with the dimers, but the ratios of the respective monomers are preferably 3% or less for the monomer, 95% or more for the dimer and 3% or less for the trimer. .

The iodine value of the dimerized fatty acid used in the modified polyester of the present invention is 20 g / 100 g or less, preferably 15 g / 100 g or less, more preferably 10 g / 100 g or less. When the iodine value of the dimerized fatty acid exceeds 20 g / 100 g, the dimerized fatty acid is colored by thermal decomposition during polymerization.

As a commercially available dimerized fatty acid satisfying the above conditions, dimer acid which is a dimerized fatty acid having 36 or 44 carbon atoms can be mentioned. Dimer acid is obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as linoleic acid or linolenic acid, or dimerizing erucic acid (22 carbon atoms), and several kinds are commercially available. Among them, Unichema International (Unichema Internationa) is a high-quality dimer acid that meets the above conditions.
l) "PRIPOL" issued by the company ("PRIPO
L ″), or various ester-forming derivatives thereof. Those compounds that meet the conditions of the polyester polymerization reaction can be used. Further, one kind or two or more kinds of the above compounds may be used in combination. May be.

In the present invention, the amount of the dimerized fatty acid residue is preferably 1 to 20 mol% of the acid component, more preferably 5 to 17 mol%, and further preferably 7 to 15 mol%. Is. The amount of dimerized fatty acid residue is 20
If it exceeds mol%, the polymerization reactivity of the polyester may be lowered, and the mechanical properties of a molded product obtained from the polyester may be lowered. On the other hand, the amount of dimerized fatty acid residue is 1 mol%
If it is less than 100%, impact resistance and pinhole resistance of the molded product obtained from polyester may decrease.

In the present invention, examples of the polyalkylene glycol residue which is the second component constituting the soft segment include those derived from those having a structure represented by the following formula. H- in _{(OC n H 2n-x R} x) m -OH ( wherein, R is a hydrocarbon radical, n is 1 to 10, x satisfies is and x ≦ 2n is 0 to 4, m is 2 to 250 Specific examples of the compound shown here include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

In the present invention, the amount of the polyalkylene glycol residue is preferably 1 to 30% by weight, more preferably 3 to 25% by weight, further preferably 5 to 20% by weight, based on the polyester. is there. When the amount of the polyalkylene glycol residue exceeds 30% by weight, the heat resistance of the polyester may be lowered and the mechanical properties of the molded product obtained from the polyester may be lowered. On the other hand, if the amount of the polyalkylene glycol residue is less than 1% by weight, the impact resistance and pinhole resistance of the molded product obtained from polyester may decrease.

In the present invention, the dimerized fatty acid residue and the polyalkylene glycol residue both act as a soft segment, so the impact resistance and the pinhole resistance are defined by the total amount of them in the polyester.
The proportion of the total amount of the soft segment consisting of the dimerized fatty acid residue and the polyalkylene glycol residue in the polyester needs to be 5 to 40% by weight, more preferably 10 to 35% by weight, More preferably, it is 15 to 30% by weight. Soft segment ratio is 40
When the content is more than 5% by weight, the polymerization reactivity and heat resistance of the polyester may be lowered, and the mechanical properties of the film obtained from the polyester may be lowered. On the other hand, if it is less than 5% by weight, impact resistance and pinhole resistance of the film obtained from polyester may be lowered.

The alkylene glycol, which is a glycol component in the present invention, is a glycol having 2 to 10 carbon atoms, specifically, ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, decanediol, 1,2-. Examples thereof include cyclohexanediol, 1,3-cyclohexanediol and 1,4-cyclohexanediol.

In the present invention, in addition to the above components, other components may be copolymerized within the range not impairing the object of the present invention. For example, as the acid component, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,
1,2-Cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, trimellitic acid, trimesic acid, etc., or their ester derivatives, p-oxybenzoic acid, p-hydroxymethylbenzoic acid, etc., as a hydroxycarboxylic acid component, or them And the alcohol component include spiroglycol, bisphenol A, bisphenol S and their ethylene oxide adducts, trimethylolpropane, and the like.

The modified polyester of the present invention comprises a crystal nucleating agent, an antioxidant, an anti-coloring agent, a pigment, a dye, an ultraviolet absorber, a release agent, a slip agent, a flame retardant, an antistatic agent, depending on its use. Inorganic and / or organic particles and the like can be blended. In particular, since the polyester of the present invention contains polyalkylene glycol, an antioxidant such as hindered phenol or benzotriazole is added to the polyester in an amount of 0.01 to 5 wt% in order to have heat resistance.
% Is preferably added.

In the present invention, the glass transition point (Tg) of polyester must be less than 55 ° C.,
It is preferably lower than 50 ° C, more preferably lower than 45 ° C.

When the Tg of the polyester is 55 ° C. or higher, the impact resistance and pinhole resistance of the polyester are deteriorated, which is not preferable.

In the present invention, the polyester has a melt viscosity (MV) at 280 ° C. of 500 poise or more and 4000 or more.
It is necessary to be poise or less, more preferably 1000 poise or more and 3500 poise or less, and further preferably 1500 poise or more and 3000.
Poise or lower. The melt viscosity of polyester is 50
When it is less than 0 poise, the polyester has no self-supporting property, and when the polyester is extruded into a film or the like, the polyester flows during film formation and the film thickness is not stable, which is not preferable. On the other hand, when the melt viscosity exceeds 4000 poise, the extrusion state is not stable and it is difficult to form a uniform film thickness, which is not preferable.

In the present invention, the color tone of polyester is L
The b value in the ab color system is preferably less than 10, more preferably less than 8, and particularly preferably less than 5.

The method for producing the polyester in the present invention is not particularly limited, but for example, it is esterified from an aromatic dicarboxylic acid and a dimerized fatty acid or a lower alkyl ester thereof, and a polyalkylene glycol and ethylene glycol. The most general method is to produce by a first-stage reaction for producing a low polymer by a reaction or a transesterification reaction and a second-stage reaction for polycondensing the low polymer. More specifically explaining the above method, dimethyl terephthalate, dimethyl dimerate, and ethylene glycol are charged into a polymerization reactor equipped with a stirrer, a nitrogen gas inlet tube, and a vacuum distillation apparatus, and the mixture is supplied at 150 to 250 while flowing nitrogen. At a temperature of ° C, heat with stirring to effect a transesterification reaction. afterwards,
Polyethylene glycol, tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4 as an antioxidant
'-Hydroxyphenyl) propinate] methane (trade name: IR-1010, manufactured by Ciba-Geigy) was added, and the pressure was gradually reduced to 200 to 3 under a reduced pressure of 0.001 to 3 Torr.
Polycondensation reaction is carried out at a temperature of 00 ° C. to obtain polyester.
At the time of this reaction, use of esterification or transesterification catalysts such as titanium, lead, zinc, calcium, magnesium, manganese compounds, polycondensation catalysts such as antimony, germanium, titanium compounds, stabilizers such as phosphorus compounds, etc. You can

The modified polyester of the present invention can be molded into fibers, films and other molded products for use. The molding method will be described below by taking a film as an example. The obtained polyester can be sufficiently dried, melt-extruded with an extruder to give an unstretched sheet, and subsequently biaxially stretched, and then heat-treated at a temperature below the melting point to give a film. At this time, polyesters other than the polyester of the present invention, for example, polyethylene terephthalate, polyethylene naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, etc. can be laminated within a range where the pinhole resistance can be maintained.

The pinhole resistance of the film obtained from polyester can be judged by the puncture strength of the obtained film and the number of pinholes in the gelbo test.

The puncture strength of a film obtained from polyester is determined by tensioning the film on a ring having a diameter of 40 mm without slack, and using a needle having a tip angle of 60 degrees and a tip R of 0.5 mm to move the center of the ring at a speed of 50 mm / min. The force at the time of puncturing is converted into a film thickness of 1 mm.

The puncture strength of the film obtained from the modified polyester of the present invention is preferably 50 kg / mm or more, more preferably 55 kg / mm or more,
More preferably, it is 60 kg / mm or more.

The number of pinholes in the film obtained from polyester is 5 ° C. in the gel botter.
The number of pinholes in the film sample which has been subjected to gelvo repetition 1000 times can be measured below.

The film obtained from the modified polyester of the present invention has few pinholes in gelvo test and shows good pinhole resistance.

The impact resistance of the film obtained from polyester was judged from the number of bags having defects in the drop bag test described later.

The film obtained from the modified polyester of the present invention does not cause bag breakage or water leakage in the drop bag test and exhibits good impact resistance.

[0036]

EXAMPLES The present invention will be described in more detail with reference to examples. The characteristics in the examples were measured as follows.

(1) Iodine Value The iodine value of the dimerized fatty acid was measured by the Wis method.

(2) Intrinsic viscosity of polyester Measured at 25 ° C. using o-chlorophenol as a solvent.

(3) Thermal Properties of Polyester 10 mg of polyester was placed in a sample pan and scanned with a differential scanning calorimeter at a rate of 10 to 20 ° C./min to measure Tg.

(4) Polyester composition analysis Polyester was hydrolyzed with alkali to isolate an acid component and a glycol component, and each component was analyzed by gas chromatography or high performance liquid chromatography. From the peak area of each component, The composition ratio was determined.

(5) Melt viscosity of polyester It was measured at 280 ° C. using a melt index.

(6) Color tone of polyester (b value) The polyester chip was placed on a glass petri dish and the color tone of the Lab color system was measured by a color machine.

(7) Puncture strength A film having a diameter of 40 mm was stretched without slack, and a needle having a tip angle of 60 ° and a tip R of 0.5 mm was used to pierce the center of the ring at a speed of 50 mm / min. The force was calculated by converting the film thickness to 1 mm.

(8) Number of pinholes In a gel bot tester, at an ambient temperature of 5 ° C., 1000
The number of pinholes in the film sample that has been subjected to gelvo repetition was measured.

(9) Dropping bag test A film sample was laminated with a polypropylene film of 50 μm, and then the film sample was tested with an impulse sealer 4
One side was sealed, 10 bags containing 200 cc of water were prepared, dropped from a height of 1 m, and the number of bags broken or leaked was measured.

Example 1 68 parts by weight of dimethyl terephthalate, iodine value 7 g / 1
00 g, 23 parts by weight of dimethyl dimer acid having 36 carbon atoms,
55 parts by weight of ethylene glycol, 0.06 parts by weight of magnesium acetate as a catalyst, 0.0 parts of diantimony trioxide
3 parts by weight was added, and the transesterification reaction was carried out in the usual way.
Then, 0.03 parts by weight of trimethyl phosphate and 10 parts by weight of polyethylene glycol as an anti-coloring agent, and tetrakis- [methylene-3- (3 ', 5'-di-
t-Butyl-4'-hydroxyphenyl) propinate] methane (trade name: IR-1010, manufactured by Ciba Geigy) was added in an amount of 0.1 part by weight, and polycondensation reaction was performed under high temperature and reduced pressure to obtain a melt viscosity of 1300 poise, specific. Viscosity 0.8
0 copolymerized polyester was obtained. The composition of the obtained polyester was such that the acid component was 95 mol% of terephthalic acid residue, 5 mol% of dimer acid residue, and 10 wt% of polyethylene glycol residue, and the dimer acid residue and the polyethylene glycol residue were combined. Soft segment amount is 20w
It was t%. The Tg of the obtained polyester was 35 ° C., which was a low Tg. The b value of the polyester was 1.0, and the color tone was good. The obtained polyester is laminated with PET on the surface layer to form a film according to a conventional method,
A film having a thickness of 15 μm and a lamination ratio of 1: 30: 1 was obtained.
The puncture strength of the obtained film was 60 kg / mm, the number of pinholes was 0, the number of defects in the drop bag test was 0, and the pinhole resistance and impact resistance were excellent.

Comparative Example 1 A copolymerized polyester having a melt viscosity of 2000 poise and an intrinsic viscosity of 0.65 was obtained in the same manner as in Example 1 except that 100 parts by weight of dimethyl terephthalate and 80 parts by weight of ethylene glycol were used. The composition of the obtained polyester was 100 mol% of terephthalic acid residues and 100 mol% of ethylene glycol residues. The obtained polyester had a Tg of 78 ° C. and ab value of 0.5. The obtained polyester was formed into a film having a thickness of 15 μm according to a conventional method.
The puncture strength of the obtained film was 40 kg / mm, the number of pinholes was 60, the number of defects in the drop bag test was 9, and both the pinhole resistance and the impact resistance were poor.

Examples 2 to 7 and Comparative Examples 2 to 6 As shown in Tables 1 and 2, polyesters of each composition and films thereof were produced by the same method as in Example 1. However, in Example 7 and Comparative Example 6, solid phase polymerization was performed to prepare a predetermined degree of polymerization (intrinsic viscosity, melt viscosity).

[0049]

[Table 1]

[Table 2] The abbreviations in the table indicate the following compounds. DMT: dimethyl terephthalate C36: dimethyl dimerate (carbon number of main chain 36) C44: dimerized fatty acid dimethyl (carbon number of main chain 44) PEG: polyethylene glycol PPG: polypropylene glycol EG: ethylene glycol Further, melt viscosity of each , Intrinsic viscosity, glass transition point, b
The values, the puncture strength, the number of pinholes, and the number of defects in the drop bag test are as shown in Table 3.

[0050]

[Table 3] All of Examples 2 to 7 are within the object range of the present invention, the obtained polyester has good moldability, and the obtained film has color tone, pinhole resistance, heat resistance and impact resistance. Was good.

On the other hand, in Comparative Example 2, since the amount of soft segment was small, Tg was large and it was outside the range of the present invention, and the film made of polyester obtained had poor pinhole resistance and impact resistance. In Comparative Example 3, the dimer acid, which is a dimerized fatty acid, had a large iodine value and was outside the range of the present invention, and the obtained polymer had a poor color tone.
In Comparative Example 4, the amount of the soft segment was large, which was out of the range of the present invention, the polymerization reactivity was poor, and the polyester obtained had a poor color tone and a small melt viscosity, so that the film could not be formed. In Comparative Example 5, the melt viscosity of the obtained polyester was small and out of the range of the present invention, and there was no self-supporting property to form a film. Comparative Example 6 had a large melt viscosity, which was out of the range of the present invention, and the castability at the time of molding was poor, so that a uniform film could not be obtained such that it partially became thick.

[0052]

EFFECTS OF THE INVENTION The modified polyester of the present invention has excellent color tone, pinhole resistance, heat resistance, impact resistance, and moldability such as film formation which have not been heretofore available.

From the modified polyester of the present invention, films, sheets and other molded products which have good pinhole resistance, heat resistance and impact resistance and are suitable for packaging can be obtained, particularly packaging films. Is suitable as

Claims (1)

[Claims] 1. A main component comprises an aromatic dicarboxylic acid residue, an alkylene glycol residue and a soft segment, and the ratio of the amount of the soft segment to polyester is 5 to 40% by weight, and the following two conditions are satisfied. Modified polyester characterized by satisfying. (1) Tg <55 ° C. (2) 500 ≦ MV ≦ 4000 (poise) (In the formula, Tg is the glass transition point of the polyester, and MV is the melt viscosity of the polyester at 280 ° C.)