JPS6257460A - Thermoplastic polymer film - Google Patents

Abstract

PURPOSE:To provide a thermoplastic polymer film containing inorganic porous microcapsules containing thermoplastic polymer, free from voids formed by the extrusion or drawing process and having excellent impact resistance, light weight and good oscillation characteristics. CONSTITUTION:(A) A thermoplastic polymer, preferably polyester or polyamide is added in an amount of 20-80wt% to (B) a microcapsule prepared from inorganic powder e.g. by an aqueous solution precipitation reaction, having a spherical form with a diameter of 0.1-100mum, containing a cavity 2 and made of a porous wall material (inorganic material such as calcium carbonate) having an average pore diameter of 10-600Angstrom and capable of including a liquid, solid or gas in the cavity in a freely releasable state, and the mixture is mixed homogeneously with a mixer, etc. The produced polymer containing inorganic porous microcapsules including the thermoplastic polymer at a filling ratio of 10-40vol% is formed to obtain the objective film having an apparent spcific gravity of 0.2-0.5.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to thermoplastic polymer films, and more particularly to thermoplastic polymer sheets loaded with lightweight inorganic porous microcapsules.

[Prior art]

Regarding the mixing of microcapsules into a plastic film, for example, Japanese Patent Application Laid-open No. 53-94920 discloses that the density of the film is reduced and the rigidity is increased to provide a speaker diaphragm. There is.

However, in films containing such conventional non-porous microcapsules, voids are formed near the microcapsules due to poor adhesion between the microcapsules and the thermoplastic polymer, especially during melt extrusion with a high draft ratio or during stretching. As a result, there was an unavoidable drawback that the mechanical properties of the obtained film, especially the impact resistance, were drastically reduced and the vibration characteristics were deteriorated.

[Purpose of the invention]

The thermoplastic polymer film of the present invention has been made to eliminate such conventional drawbacks, and has no voids caused by extrusion or stretching, has excellent impact resistance, is lightweight, and has good vibration characteristics. The object is to provide a plastic polymer film.

[Structure of the invention]

The thermoplastic polymer film of the present invention that achieves the above object has a thermoplastic polymer with a filling rate of 10 to 4.
20 to 80% by weight of inorganic porous microcapsules encapsulated at 0% by volume, and the apparent specific gravity is 0%.
．． It is characterized by being 2 to 0.5.

The thermoplastic polymer in the present invention exhibits plastic flow upon heating, and is primarily a linear polymer in chemical structure, but may also contain low molecular weight oligomers.

Typical examples include polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polybutadiene, polystyrene, and polymethylpentene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polycarbonate. Halogenated polymers represented by polyester, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polyvinyl fluoride, etc.
Polyamides such as polyhexamethylene adipate (nylon 66), polyε-caprolactam (nylon 6), and nylon 610, as well as vinyl polymers such as polyacrylonitrile and polyvinyl alcohol, polyacetals, polyethersulfones, polyetherketones, and polyphenylenes. These include ether, polysulfone, polyphenylene sulfide, copolymers and mixtures thereof, and are not particularly limited, but in the case of the present invention, polyester, polyphenylene sulfide, polyamide, polysulfone, and polyvinylidene fluoride are preferably used.

In addition, the inorganic porous microcapsules (hereinafter simply referred to as microcapsules) used in the present invention are minute particles with a diameter of 0.1 μm to 100 μm.
As shown in Fig. 1, the wall material 1 is a porous, spherical container with an average pore size of 10 to 600, and has a hollow part 2 inside. It is also possible to freely enclose and release solids and gases.

As a typical manufacturing method, for example, Japanese Patent Publication No. 54-625
Publication No. 1, Special Publication No. 57-55454, Special Publication No. 55
This is the "interfacial reaction method" described in Publication No. 43404, that is, the method of preparing inorganic powder by an aqueous solution precipitation reaction, but in the preparation process, by using a water-in-oil emulsion Hollow・
It can be manufactured by adjusting spherical and porous inorganic powder particles.

The inorganic wall material constituting the microcapsules is not particularly limited, and may include calcium carbonate, barium carbonate,
Alkaline earth metal carbonates such as magnesium carbonate, alkaline earth metal silicates such as calcium silicate, barium silicate, and magnesium silicate, alkaline earth metal phosphates such as calcium phosphate, barium phosphate, and magnesium phosphate, calcium sulfate, Alkaline earth metal sulfates such as barium sulfate and magnesium sulfate, metal oxides such as silicic anhydride, aluminum oxide, zinc oxide, iron oxide, titanium oxide, cobalt oxide, nickel oxide, and manganese oxide, iron hydroxide, and nickel hydroxide. , metal hydroxides such as aluminum hydroxide, calcium hydroxide, and chromium hydroxide, metal silicates such as zinc silicate, aluminum silicate, and silicate steel, zinc carbonate, aluminum carbonate, cobalt carbonate, nickel carbonate,
Examples include metal carbonates such as basic copper carbonate.

In the case of the present invention, oxides such as SiO□ and TiO2 are particularly preferred.

The size of the microcapsules is variable in the range of 0.1 to 100 μm, and in the case of the present invention, sharp spherical ones with an average particle size distribution of 0.1 to 2 μm are particularly preferred since they are compatible with the thermoplastic polymer. , is preferable because of its good distribution.

The pore diameter of the capsule particle surface is 20 as measured by the BET method.
600 people, but in the case of the present invention, 20 to 10
A distribution having a main pore size in the range of 0.000 to 0.000000000000 is preferred.

Of course, a completely spherical shape is preferable in terms of dispersibility, fluidity, slipperiness, smoothness, abrasion resistance, etc.

Since they are microspheres and porous with pores, the particle surface is extremely large and has a diameter of 100 to 1000 r.
rr/g, and the apparent specific gravity is also small, and in the present invention, those with a specific gravity of 0.1 to 0.4 are preferred.

In addition, the thickness of the wall of this microcapsule is also 0.01~
It can be freely changed to 5 μm, and this is determined not only by mechanical properties such as deformation and destruction due to external force, but also by the volume ratio of the hollow part 2 of the microcapsule shown in the attached diagram.

The thermoplastic polymer is contained in the microcapsules contained in the thermoplastic polymer film of the present invention at a filling rate of 10 to 10.
Must be filled at 40% by volume.

That is, when the filling rate is 10% by volume without grooves, the adhesion between the microcapsules and the thermoplastic polymer is weak, and therefore, when high draft extrusion or stretching is performed, voids are generated near the microcapsules. However, the mechanical properties become inferior. On the other hand, if the filling rate exceeds 40% by volume, it will not be possible to obtain a film with an apparent low specific gravity, and the film will not be lightweight or an energy absorber.

Further, the porosity of the microcapsules is preferably 60 to 90% by volume.

In the present invention, the amount of inorganic porous microcapsules added to the thermoplastic polymer is 20 to 80% by weight.

If the amount of microcapsules added is less than 20% by weight,
The apparent weight of the film of the present invention cannot be reduced if the specific gravity exceeds 0.5, and conversely, if the specific gravity exceeds 80% by weight, even if porous microcapsules are used, many voids will occur near the microcapsules, resulting in poor mechanical properties. This is a significant decrease in

Furthermore, in the present invention, the apparent specific gravity of the thermoplastic polymer film to which the microcapsules are added is preferably 0.2 to 0.5.

If the apparent specific gravity is less than 0.2, only inferior mechanical properties will be obtained, and if it exceeds 0.5, it will not be possible to reduce the weight and will become a shock absorber. I don't like it because it doesn't work.

Next, the method for producing the thermoplastic polymer film of the present invention will be described, but the present invention is not necessarily limited thereto.

That is, porous inorganic microcapsules are added to a thermoplastic polymer, and the microcapsules are uniformly mixed into the polymer using a mixer or dryer.

Alternatively, the microcapsules can be added and polymerized in a step immediately before the completion of polymerization of the thermoplastic polymer, but in the case of the present invention, the former case, that is, addition after the completion of polymerization of the thermoplastic polymer is preferable.

The thermoplastic polymer thus obtained, alone or with the addition of other additives, is fed into an extruder in a conventional manner, melted at a temperature above the melting point of the polymer, and extruded into a film from the die. Extrusion, casting onto a casting drum or belt using an appropriate close contact method, such as an air knife method, an electrostatic application method, a press roll method, etc., is cooled and solidified, and is formed into a film.

It is clear that stretching and rolling in the longitudinal and transverse directions, as well as heat treatment, embossing, calendering, surface treatment, etc., may be carried out as necessary.

The thickness of the film obtained in this way is not particularly limited, but it is 1 mm or less, preferably 0.5 mm or less, more preferably 190 μm or less, and depending on the use, it may be 50 μm or less.
m or less is preferable.

〔Effect of the invention〕

As described above, according to the thermoplastic polymer film of the present invention, the thermoplastic polymer has a filling rate of 10
20-8 microcapsules encapsulated at ~40% by volume
0% by weight is added, and the apparent specific gravity is 0.2 to 0.
．． 5, the following effects can be achieved.

(1) In the present invention, inorganic porous spherical microcapsules are added to a thermoplastic polymer, and the thermoplastic polymer is filled in the capsules at 10 to 40% by volume, so that extrusion is possible. It is possible to prevent the generation of voids near the microcapsules during stretching.

This is presumably because the polymer within the microcapsule forms a strong physical bond with the thermoplastic polymer outside the capsule through the porous wall of the capsule.

Therefore, the thermoplastic polymer film according to the present invention can prevent a decrease in mechanical strength due to the generation of voids, unlike conventional non-porous microcapsule-containing films, and can provide a sheet with excellent impact resistance. can be obtained.

(2) Also, in the present invention, for example, the apparent specific gravity is 0.1 to 0.
20 inorganic porous microcapsules with a low specific gravity of 4
Since it is added in a large amount of ~80% by weight, the apparent specific gravity of the obtained film is as small as 0.2 to 0.5, and a lightweight film is provided.

(3) As described above, the thermoplastic polymerization-resistant film of the present invention is lightweight and has excellent mechanical strength, especially abrasion resistance, so it has good vibration characteristics and is suitable for use as speaker cones and diaphragms. used.

Further, in the present invention, since no voids are generated in the film and minute microcapsules are added, an extremely thin film can be obtained, which is suitable for packaging applications.

Next, the characteristic measuring method used in the present invention will be described.

(1) Mechanical strength (impact resistance): Measure the impact resistance value of the sample according to JIS z1707. Those with an IR value of 6 or more: ○ Those with an IR value of 3 to 5. △ The ones with an IR value of 2 or less. ×

(2) Pore diameter: BET using Digisoap 2500 model manufactured by Shimabara Manufacturing Co., Ltd.
It is determined by analyzing the sorption isotherm curve using the BJH method.

(3) Apparent specific gravity of particles: The apparent specific gravity is given by 1 g of inorganic microcapsules.

(4) Specific surface area CBET method): (For example, J, Am, Chem, Soc, 38.22
19 (1916). ) Adsorb nitrogen molecules onto the particle surface, measure the amount of adsorption, calculate the volume of adsorbed gas when the entire surface is covered with a monomolecular adsorption layer using the following formula (1), and calculate this by one nitrogen molecule. The number of molecules was determined by dividing by the volume of . This number of molecules and the following formula (2
) The specific surface area was obtained by multiplying by the volume σ occupied by one adsorbed molecule on the surface.

V = VmCP/(Ps-P) (1+ (C-1)
P/Ps ) (1) where Vm is the volume of adsorbed molecules when the entire surface is covered with a monomolecular adsorption layer, ■ is the pressure p
The volume of adsorbed gas at , P indicates the pressure, Ps is the saturated vapor pressure, and C is a constant.

σ= 1.091 (M/NP)
(2) Here, σ is the area occupied by one adsorbed molecule on the surface, M is the molecular weight, N is Avogadro's number, and p is the density of the adsorbed molecule layer on the surface.

(5) Average particle size: Capture images of particles with a scanning electron microscope,
The number average diameter φn is obtained by connecting the light density produced by the particles to an image analyzer (for example, QTM900, manufactured by Nippon Regulator) and performing the following numerical processing.

Σdn/Σn=φn However, n is the number and d is the actual pore diameter.

(6) Porosity: The film was dissolved in a good solvent for the polymer, and the added inert fine particles were separated by centrifugal sedimentation.

The separated inert fine particles were heated under a vacuum of 1 Qtorr at 100
After sufficiently drying at a temperature of ℃, the separated inert fine particles 1
Based on the ash content test of gr@JIs C2330, it was heated at 800°C for 4 hours in an air atmosphere, and the weight B (unit: gr) of the isolated inert fine particles obtained at this time was measured at 25°C, 5
Measurement was performed under an atmosphere of 0% RH.

Furthermore, the total pore volume A (unit: cc) of the isolated inert fine particles is
) was determined by the infiltration method shown below.

From these values, the porosity was determined using the following formula (11).

However, ρ is the density (g/cc) of the polymer in an amorphous state at 25°C.

Note that the method for determining the total pore volume (cc) using the above-mentioned infiltration method is to dissolve a certain amount C (gr) of isolated inert fine particle sample in a solvent (
After boiling in carbon tetrachloride at a temperature of 76 to 78° C. for 5 hours, only the particle sample is separated by centrifugal sedimentation. then 60
Dry with hot air at ~70℃ for 30 minutes, and then
Measure itD(gr).

From these values, the total pore volume was determined using the following formula (2).

(7) Filling rate: The filling rate is determined by the following formula.

Filling rate (volume %) = (100 - porosity (χ)) (8
) Addition amount of microcapsules in thermoplastic polymer: Based on the ash content test of JIS C2330, thermoplastic polymer A (unit: gr) was heated at 800°C in an air atmosphere at 4.
The weight of the residue obtained at this time is B (unit: gr
), it is determined by (A/B)X100.

(9) Apparent specific gravity of film: Value at 25°C (g/cc) measured according to ASTM D792.

Examples of the present invention will be described below.

〔Example〕

Example 1, Comparative Example 1.2 A spherical porous hollow silica having an average particle diameter of 2 μm, a pore diameter of 200 μm, and an apparent specific gravity of 0.2 is abbreviated as polyethylene terephthalate C or less, PET. Intrinsic viscosity (η) =0.6
5. Diethylene glycol 1.5 mol % copolymerization] was added in an amount of 35% by weight after the completion of polymerization, and was uniformly dispersed.

After drying the obtained PBT at 180°C for 2 hours, it was fed to an extruder, and after being melted at 280°C, it was produced at 100Kg/cd.
The above filtration pressure was applied to discharge the mixture from the nozzle, and while applying an electrostatic charge, the mixture was cast onto a mirror-finished chrome-plated roll maintained at 35° C. to obtain a non-oriented sheet.

This sheet was stretched 3.8 times in the machine direction at 98°C, then 4 times in the transverse direction at 95°C, and then 5 times in the width direction at 200°C.
% relaxation for 7 seconds.

The thickness of the obtained biaxially oriented film has an apparent specific gravity of 0.
4. The thickness is 150 μm, and the properties of this film are shown in the table.

As a comparative example, polyvinyl chloride foam plastic
The properties of the sheet (Comparative Example 2) and the case of adding conventional non-porous hollow microcapsules (Comparative Example 1) are also shown.

(The following is a blank space) As is clear from this table, a thermoplastic polymer film that is lightweight and has good mechanical strength can be obtained only in the case of the present invention.

[Brief explanation of drawings]

The figure is an enlarged sectional view of an inorganic porous microcapsule used in the present invention. 1...Wall material, 2...Hollow part.

Claims (1)

[Claims] The thermoplastic polymer has a filling rate of 10 to 40
Inorganic porous microcapsules encapsulated in a volume% of 2
0 to 80% by weight, and the apparent specific gravity is 0.
A thermoplastic polymer film characterized in that it has a molecular weight of 2 to 0.5.