JP2010247386A - Method of molding polypropylene high-frequency welder molded sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene high-frequency welder molded sheet excellent in high-frequency welder workability, and excellent in balance of transparency, flexibility and heat resistance, and a method of molding the same. <P>SOLUTION: This method of molding of the polypropylene high-frequency welder molded sheet includes molding polypropylene sheets using a propylene-ethylene block copolymer under a specified condition, after the sheets are layered, using a high-frequency welder. (A-i) The propylene-ethylene block copolymer is polymerized sequentially with 30-95 wt.% of propylene-ethylene random copolymer component A1 containing 0.3-7 wt.% of ethylene, in the first process, and with a propylene-ethylene random copolymer component A2 containing ethylene more by 3-20 wt.% than an ethylene content of the component A1, in the second process, using a metallocene catalyst. (A-ii) An MFR is within a range of 0.1-30 g/10 min. (A-iii) A tan δ curve has a single peak at 0°C or less, in a solid viscoelastic measurement (DMA). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for forming a polypropylene-based high-frequency welder molded sheet that can be substituted for soft polyvinyl chloride (PVC), and more specifically, a polypropylene sheet using a specific propylene-ethylene block copolymer is overlapped. Then, it is related with the shaping | molding method of the polypropylene type high frequency welder shaping | molding sheet | seat shape | molded on specific conditions using a high frequency welder.

Soft vinyl chloride resin (PVC) is inexpensive, excellent in transparency, gloss and flexibility, and as industrial materials such as stationery such as card folders and desk mats, general household goods, leather for automobile interiors, pipes, etc. Widely used.
However, from the viewpoint of environmental protection and the like, olefination of soft PVC sheets is currently being promoted. A typical example thereof is an agricultural film. For example, Patent Document 1 discloses an agricultural multilayer film made of an olefin resin and having excellent antifogging sustainability.
In addition to the agricultural film field, various proposals have been made for olefination of multilayer films, for example, for packaging foods. For example, Patent Document 2 discloses that high-frequency welder processing is achieved by using an ethylene resin having a polar group as an intermediate layer and a propylene resin as a surface layer.

However, in the conventional technique, the multilayered sheet has a problem in the adhesiveness between the ethylene resin and the propylene resin, and particularly has a problem in the heat resistance of the internal ethylene resin.
At present, a polypropylene sheet that satisfies conditions suitable for high-frequency welder processing using a propylene resin having excellent heat resistance has not yet been found.

JP-A-9-18393 Japanese Patent Laid-Open No. 11-333998

  An object of the present invention is to provide a polypropylene-based high-frequency welder molded sheet that is excellent in high-frequency welder processability and excellent in balance of transparency, flexibility, and heat resistance, and a method for forming the high-frequency welder molded sheet.

The inventors of the present invention have a specific component composition, molecular weight distribution, composition distribution, etc. by multi-stage polymerization using a metallocene catalyst, and also have solid viscoelastic characteristics and elution characteristics in temperature-temperature elution fractionation. A series of research and development was conducted on the propylene-ethylene block copolymer, and as a result, an application was made as a prior invention (see Japanese Patent Application Laid-Open No. 2005-132999). In order to develop a polypropylene high-frequency welder molding sheet with improved properties, we will use this prior invention to realize a polypropylene high-frequency welder molding sheet with excellent transparency, flexibility and heat resistance. The present inventors studied diligently about the molding method.
And, as a result of intensive studies to solve the above problems, the present inventors, after overlapping a polypropylene sheet using a specific propylene-ethylene block copolymer, etc., using a high frequency welder, It has been found that when molded under specific conditions, a polypropylene high-frequency welder molded sheet having excellent transparency, flexibility and heat resistance can be obtained, and the present invention has been completed.

That is, according to the first invention of the present invention, after the polypropylene sheets using the propylene-ethylene block copolymers satisfying the conditions (Ai) to (A-iii) are overlaid, or the sheets After forming the end faces of each other, a high-frequency welder is used to form a polypropylene-based high-frequency welder molded sheet, which is molded under the condition that the anode current [unit: ampere (A)] satisfies the following formula (1): A method is provided.
1.0 ≧ anode current ≧ 0.0028 × sheet thickness (μm) +0.1271 (1) Formula (A-i) In the first step, 0.3 to 7% by weight using a metallocene catalyst 30 to 95% by weight of propylene-ethylene random copolymer component (A1) containing ethylene in the second step, and propylene-ethylene random containing ethylene in the second step in an amount 3 to 20% by weight greater than the ethylene content of component (A1) It is a propylene-ethylene block copolymer formed by successively polymerizing 5 to 70% by weight of the copolymer component (A2).
(A-ii) Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is in the range of 0.1 to 30 g / 10 minutes.
(A-iii) The temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA) has a single peak at 0 ° C. or lower.

According to a second invention of the present invention, in the first invention, the polypropylene-based high frequency wave characterized in that the polypropylene-based sheet is a multilayer sheet having a layer using a propylene-ethylene block copolymer as an outermost surface layer. A method of forming a welder molded sheet is provided.
According to a third aspect of the present invention, there is provided a method for forming a polypropylene high-frequency welder molded sheet according to the first or second aspect, wherein the polypropylene sheet has a thickness of 10 to 250 μm. .
Furthermore, according to the fourth invention of the present invention, there is provided a molded product formed by the method for forming a polypropylene-based high-frequency welder molded sheet according to any one of the first to third inventions.

As described above, the present invention relates to a method for forming a polypropylene-based high-frequency welder molded sheet, and preferred embodiments thereof include the following.
(1) In the first invention, a part of the polypropylene sheet and a part of the front or back surface of the same or different polypropylene sheet are superposed so as to contact each other, and then molded using a high frequency welder. A method for molding a polypropylene-based high-frequency welder molded sheet, characterized in that:

  The polypropylene-based high-frequency welder molded sheet obtained by the molding method of the present invention has a remarkable effect of being excellent in the balance of transparency, flexibility and heat resistance. And the molding method of the polypropylene type high frequency welder molding sheet of this invention can obtain the high frequency welder molding sheet which has such outstanding performance easily. In addition, the polypropylene-based high-frequency welder molded sheet obtained by the molding method of the present invention is excellent in transparency, heat resistance, flexibility, and high-frequency welder moldability. It can be suitably used for various packaging materials such as industrial materials such as tent sheets and curing sheets.

It is a graph which shows the elution amount curve and elution amount integration of PP-1. It is a graph which shows the solid viscoelasticity measurement of PP-1. It is a graph which shows the solid viscoelasticity measurement of PP-3. It is a graph which shows the welder adhesiveness in the relationship between an anode electric current and sheet | seat thickness.

The method for forming a polypropylene-based high-frequency welder molded sheet according to the present invention includes a method in which a polypropylene sheet using a propylene-ethylene block copolymer satisfying the conditions (A-i) to (A-iii) is overlaid, or After aligning the end faces of the sheets, the sheet is molded under the condition that the anode current [unit: ampere (A)] satisfies the following formula (1) using a high frequency welder.
1.0 ≧ anode current ≧ 0.0028 × sheet thickness (μm) +0.1271 (1) formula

(Ai) 30 to 95% by weight of a propylene-ethylene random copolymer component (A1) containing 0.3 to 7% by weight of ethylene in the first step using a metallocene catalyst, the second step A propylene-ethylene block copolymer obtained by sequentially polymerizing 5 to 70% by weight of a propylene-ethylene random copolymer component (A2) containing 3 to 20% by weight of ethylene more than the ethylene content of the component (A1) Be.
(A-ii) Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is in the range of 0.1 to 30 g / 10 minutes.
(A-iii) The temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA) has a single peak at 0 ° C. or lower.

  Hereinafter, the molding method of the polypropylene type high frequency welder molded sheet of the present invention will be described in detail for each item.

1. Propylene-ethylene block copolymer The propylene-ethylene block copolymer which satisfy | fills the conditions of (Ai)-(A-iii) is used for the shaping | molding method of the polypropylene type high frequency welder molding sheet | seat of this invention.
(Ai) 30 to 95% by weight of a propylene-ethylene random copolymer component (A1) containing 0.3 to 7% by weight of ethylene in the first step using a metallocene catalyst, the second step A propylene-ethylene block copolymer obtained by sequentially polymerizing 5 to 70% by weight of a propylene-ethylene random copolymer component (A2) containing 3 to 20% by weight of ethylene more than the ethylene content of the component (A1) Be.
(A-ii) Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is in the range of 0.1 to 30 g / 10 minutes.
(A-iii) The temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA) has a single peak at 0 ° C. or lower.

(1) Basic Requirements The propylene-ethylene block copolymer according to the present invention is a propylene-ethylene random copolymer component (A1) having an ethylene content of 0.3 to 7 wt% in the first step using a metallocene catalyst. ) In the second step, the ethylene content is 3 to 20 wt% higher than the component (A1) in the first step (that is, for example, the ethylene content of the component (A1) is 5 wt%) It is obtained by successively polymerizing 70 to 5 wt% of a propylene-ethylene random copolymer component (A2) having an ethylene content of 8 to 25 wt%.
Such a propylene-ethylene block copolymer is commonly called a so-called block copolymer, but is in a blended state of component (A1) and component (A2), and both are bonded by polymerization. It is not what you have.

(2) Component (A1) (2-1) Ethylene content in component (A1) [E (A1)]:
The component (A1) produced in the first step has a relatively high melting point, crystallinity, and ethylene content of 0.3 to 7 wt% in order to suppress stickiness and develop heat resistance. It must be an ethylene random copolymer. When the ethylene content is less than 0.3 wt%, the flexibility is insufficient, and when the ethylene content exceeds 7 wt%, the melting point becomes too low and the heat resistance is deteriorated, so the ethylene content is preferably 0.3-7 wt%. Is 0.5 to 6 wt%.
In addition, although a component (A1) shows the improved softness | flexibility, transparency, and heat resistance also with a propylene homopolymer, when a component (A1) is a propylene homopolymer, it is enough, maintaining transparency. In order to exhibit such flexibility, it is necessary to extremely increase the proportion of the component (A2) to be described later, which may cause remarkable deterioration such as heat resistance, stickiness and blocking.
On the other hand, when the component (A1) is a propylene-ethylene random copolymer, the melting point of the component (A1) itself is lowered, so that the heat resistance seems to deteriorate, but in order to exhibit sufficient flexibility, Since the amount of the necessary component (A2) can be suppressed, the heat resistance of the block copolymer as a whole is rather improved and the stickiness and blocking are less deteriorated, which is preferable.
Furthermore, by reducing the melting point, even when the molding temperature during sheet molding is lowered, sufficient molding stability can be obtained, so that an excellent sheet with very little generation of odor due to heating can be obtained. .
From these viewpoints, the ethylene content in the component (A1) is preferably 0.5 wt% or more, more preferably 1.5 wt% or more.

(2-2) Ratio of component (A1) in the block copolymer:
If the proportion of the component (A1) in the propylene-ethylene block copolymer is too large, the effect of improving the flexibility and transparency of the propylene-ethylene block copolymer and the high-frequency welder processability cannot be sufficiently exhibited. . Therefore, the ratio of the component (A1) is 95 wt% or less, preferably 85 wt% or less, more preferably 70 wt% or less.
On the other hand, if the proportion of the component (A1) becomes too small, stickiness increases and the heat resistance is remarkably deteriorated. Therefore, the proportion of the component (A1) is 30 wt% or more, preferably 40 wt% or more. is there.

(3) Component (A2) (3-1) Ethylene content in component (A2) [E (A2)]:
The propylene-ethylene random copolymer component (A2) produced in the second step is a component necessary for improving the flexibility and transparency of the propylene-ethylene block copolymer and the high frequency welder processability.
Here, the component (A2) needs to have an ethylene content in a specific range in order to sufficiently exhibit the above effects.
That is, in the propylene-ethylene block copolymer according to the present invention, the lower the crystallinity of the component (A2) relative to the component (A1), the greater the flexibility improvement effect, and the crystallinity is propylene-ethylene random copolymer. Since it is controlled by the ethylene content in the coalescence (A2), the ethylene content [E (A2)] in the component (A2) is 3 wt% or more than the ethylene content [E (A1)] in the component (A1). If it is not much, the effect cannot be exhibited, and it contains more ethylene than the component (A1), preferably 6 wt% or more, more preferably 8 wt% or more.
Here, when the difference in ethylene content between the component (A1) and the component (A2) is defined as E (gap) (= E (A2) −E (A1)), E (gap) is 3 wt% or more, preferably It is 6 wt% or more, more preferably 8 wt% or more.
On the other hand, if the ethylene content is excessively increased in order to lower the crystallinity of the component (A2), the difference E (gap) in the ethylene content between the component (A1) and the component (A2) becomes large, and the matrix and domain are separated. It takes a phase separation structure and transparency is lowered. This is because polypropylene originally has low compatibility with polyethylene, and even in the case of propylene-ethylene random copolymers, although the ethylene content is different, the mutual compatibility decreases as the difference in ethylene content increases. is there. The upper limit of E (gap) may be in a range where the peak of tan δ is single by solid viscoelasticity measurement described later. For this reason, E (gap) is 20 wt% or less, preferably 18 wt% or less. More preferably, it is 16 wt% or less.

(3-2) Ratio of component (A2) in the block copolymer:
If the proportion of component (A2) is too large, stickiness will increase, blocking will be worsened, and the heat resistance will be significantly reduced. Therefore, the proportion of component (A2) must be suppressed to 70 wt% or less. .
On the other hand, if the proportion of the component (A2) becomes too small, the effect of improving flexibility and welder workability cannot be obtained. Therefore, the proportion of (A2) needs to be 5 wt% or more, preferably 15 wt%. % Or more, more preferably 30 wt% or more.

(4) Melt flow rate (MFR) of block copolymer
The MFR of the propylene-ethylene block copolymer used in the polypropylene welder processing sheet according to the present invention needs to be in the range of 0.1 to 30 g / 10 min. In the present invention, if the MFR is too low, surface roughness called shark skin or melt fracture occurs on the surface of the sheet, and the transparency and appearance are significantly impaired. On the other hand, if the MFR is too high, the molding stability of the sheet is impaired and the impact resistance is lowered, which is not preferable.
Therefore, in the present invention, the MFR of the propylene-ethylene block copolymer must be in the range of 0.1 to 30 g / 10 min, and the range of 0.5 to 10 g / 10 min is the molding stability and sheet appearance. From the viewpoint of balance of physical properties, it is preferable.
The melt flow rate (MFR) in the present invention is in accordance with JIS K7210A method, condition M, test temperature: 230 ° C., nominal load: 2.16 kg, die shape: diameter 2.095 mm, length 8.00 mm. It is measured.

(5) Specific by solid viscoelasticity (5-1) Specification by peak of tan δ curve:
The propylene-ethylene block copolymer used in the method for forming a polypropylene-based high-frequency welder molded sheet of the present invention has a tan δ curve of 0 ° C. or less in a temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA). It is necessary to have a single peak.
On the other hand, when the propylene-ethylene block copolymer has a phase separation structure, the glass transition temperature of the amorphous part contained in the component (A1) and the glass transition temperature of the amorphous part contained in the component (A2) are Since they are different, there are a plurality of peaks in the tan δ curve. In this case, there arises a problem that the transparency is remarkably deteriorated.
Whether or not the phase separation structure is taken can be determined by the tan δ curve in the measurement of solid viscoelasticity. The avoidance of the phase separation structure that affects the transparency of the molded article is a single peak at 0 ° C. or less. Is brought about by having
In the present invention, it is necessary that the tan δ curve in the solid viscoelasticity measurement has a single peak in order to exhibit transparency.
Examples of tan δ curves according to the present invention and examples of tan δ curves without a single peak for comparison are shown in FIGS. 2 and 3 as examples in polymerization production examples 1 and 3, respectively. It is shown.

(5-2) Measurement method:
Specifically, solid viscoelasticity measurement is performed by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece and detecting the generated stress.
In the present invention, the frequency is 1 Hz, and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured. Further, it is recommended that the magnitude of distortion is about 0.1 to 0.5%. Then, the storage elastic modulus and the loss elastic modulus are obtained from the obtained stress by a known method, and the loss tangent (= loss elastic modulus G ″ / storage elastic modulus G ′) defined by these ratios is determined as the temperature. When plotted against, a tan δ curve is obtained, and in the present invention, a sharp single peak is shown in the temperature range of 0 ° C. or lower. In general, the peak of the tan δ curve at 0 ° C. or lower is for observing the glass transition of the amorphous part, and here, this peak temperature is defined as the glass transition temperature [Tg (° C.)].

(6) Regarding identification of ethylene content E (A1) and E (A2) and component amounts W (A1) and W (A2) of components (A1) and (A2) Components (A1) and (A2) Each ethylene content and component amount of can be specified by the material balance at the time of polymerization (material balance), but in order to specify these more accurately, the following analysis (fractionation method) should be used. Is desirable.

(6-1) Identification of each component amount W (A1) and W (A2) by temperature rising elution fractionation method (TREF):
(I) Temperature rising elution fractionation method:
A technique for evaluating the crystallinity distribution of propylene-ethylene block copolymer by temperature rising elution fractionation (TREF) is well known to those skilled in the art. The law is shown.
G. Glockner, J. et al. Appl. Polym. Sci. : Appl. Polym. Symp. 45, 1-24 (1990)
L. Wild, Adv. Polym. Sci. 98, 1-47 (1990)
J. et al. B. P. Soares, A .; E. Hamielec, Polymer; 36, 8, 1639-1654 (1995)

  The propylene-ethylene block copolymer in the present invention is greatly different in the crystallinity of each of the components (A1) and (A2), and is produced using a metallocene catalyst so that the respective crystallinity distributions are Since it is narrow, there are very few intermediate components of both, and it is possible to separate both with high accuracy by TREF.

In the TREF elution curve obtained as a plot of elution amount (dWt% / dT) against temperature by the temperature rising elution fractionation method (TREF) in the temperature range of −15 ° C. to 140 ° C. using o-dichlorobenzene solvent, (A1) and (A2) show their elution peaks at the respective temperatures T (A1) and T (A2) due to the difference in crystallinity, and the difference is sufficiently large, so that the intermediate temperature T (A3) (= In {T (A1) + T (A2)} / 2), separation is possible.
Further, the lower limit of the TREF measurement temperature is −15 ° C. in the apparatus used for this measurement, but in the case of the component (A2) having very low crystallinity or an amorphous component, There is a case where no peak is shown in the measurement temperature range (at this time, the concentration of the component (A2) dissolved in the solvent is detected at the measurement temperature lower limit (that is, −15 ° C.)).
In this case, T (A2) is considered to exist below the lower limit of the measurement temperature, but the value cannot be measured. In such a case, T (A2) is set at the lower limit of the measurement temperature. It is defined as a certain −15 ° C.
Here, if the integrated amount of the component eluted before T (A3) is defined as W (A2) wt%, and the integrated amount of the component eluted at T (A3) or higher is defined as W (A1) wt%, W (A2) Corresponds approximately to the amount of the low-crystalline or amorphous component (A2), and the integrated amount W (A1) of the component eluted at T (A3) or higher is a component with relatively high crystallinity ( Almost corresponds to the amount of A1).
In addition, the example of a TREF elution curve is illustrated by FIG. 1 as an example in superposition | polymerization manufacture example A-1.

(Ii) TREF measurement method:
In the present invention, the measurement is specifically performed as follows. A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) at 140 ° C. to obtain a solution. After this is introduced into a TREF column at 140 ° C., it is cooled to 100 ° C. at a temperature decreasing rate of 8 ° C./min, subsequently cooled to −15 ° C. at a temperature decreasing rate of 4 ° C./min, and held for 60 minutes. Thereafter, a component of −15 ° C. o-dichlorobenzene (containing 0.5 mg / ml BHT), which is a solvent, flows through the column at a flow rate of 1 ml / min, and is dissolved in o-dichlorobenzene at −15 ° C. in the TREF column. Is eluted for 10 minutes, and then the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.

(6-2) Identification of ethylene content E (A1) and E (A2) in each component:
(I) Separation of components (A1) and (A2):
Based on T (A3) obtained by the previous TREF measurement, a soluble component (A2) in T (A3) and insoluble in T (A3) by a temperature rising column fractionation method using a preparative fractionator It fractionates with the component (A1) of a component, The ethylene content of each component is calculated | required by NMR.
The temperature rising column fractionation method is a measurement method as disclosed in, for example, Macromolecules 21 314-319 (1988). Specifically, the following method was used in the present invention.

(Ii) Sorting conditions:
A cylindrical column having a diameter of 50 mm and a height of 500 mm is packed with a glass bead carrier (80 to 100 mesh) and maintained at 140 ° C. Next, 200 ml of a sample o-dichlorobenzene solution (10 mg / ml) dissolved at 140 ° C. is introduced into the column. Thereafter, the temperature of the column is cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./hour. After holding at 0 ° C. for 1 hour, the column temperature is heated to T (A3) at a heating rate of 10 ° C./hour and held for 1 hour. Note that the temperature control accuracy of the column through a series of operations is ± 1 ° C.
Next, while maintaining the column temperature at T (A3), 800 ml of o-dichlorobenzene of T (A3) is allowed to flow at a flow rate of 20 ml / min, whereby components soluble in T (A3) present in the column are obtained. Elute and collect.
Next, the column temperature is increased to 140 ° C. at a rate of temperature increase of 10 ° C./min, left at 140 ° C. for 1 hour, and then 800 ml of o-dichlorobenzene as a solvent at 140 ° C. is flowed at a flow rate of 20 ml / min. , T (A3) is eluted and recovered.
The polymer-containing solution obtained by fractionation is concentrated to 20 ml using an evaporator and then precipitated in 5 times the amount of methanol. The precipitated polymer is collected by filtration and dried overnight in a vacuum dryer.

(Iii) Determination of ethylene content by ¹³ C-NMR:
The ethylene content of each of the components (A1) and (A2) obtained by the above fractionation is determined by analyzing a ¹³ C-NMR spectrum measured according to the following conditions by a proton complete decoupling method.
Model: GSX-400 manufactured by JEOL Ltd. or equivalent device (carbon nuclear resonance frequency of 100 MHz or more)
Solvent: o-dichlorobenzene / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / ml
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Integration count: 5,000 times or more The attribution of the spectrum may be performed with reference to, for example, Macromolecules 17 1950 (1984). The attribution of spectra measured under the above conditions is as shown in Table 1. In the table, symbols such as S _αα represent Carman et al. (Macromolecules 10 536 (1977)), P represents a methyl carbon, S represents a methylene carbon, and T represents a methine carbon.

Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six types of triads of PPP, PPE, EPE, PEP, PEE, and EEE may exist in the chain. As described in Macromolecules 15 1150 (1982) and the like, the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions (1) to (6).
[PPP] = k × I (T _ββ ) (1)
[PPE] = k × I (T _βδ ) (2)
[EPE] = k × I (T _δδ ) (3)
[PEP] = k × I (S _ββ ) (4)
[PEE] = k × I (S _βδ ) (5)
[EEE] = k × {I (S _δδ ) / 2 + I (S _γδ ) / 4} (6)

Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads.
Therefore,
[PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1 (7)
It is. Further, k is a constant, I indicates spectral intensity, and for example, I (T _ββ ) means the intensity of a peak at 28.7 ppm attributed to T _ββ .
By using the relational expressions (1) to (7) above, the fraction of each triad is obtained, and the ethylene content is obtained from the following expression.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100
In addition, the propylene random copolymer of the present invention contains a small amount of a propylene hetero bond (2,1-bond and / or 1,3-bond), thereby producing a minute peak shown in Table 2.

In order to obtain an accurate ethylene content, it is necessary to include these peaks derived from heterogeneous bonds in the calculation, but it is difficult to completely separate and identify the peaks derived from heterogeneous bonds. Since the ethylene content of the present invention is small, the relational expressions (1) to (7) are used in the same manner as the analysis of the copolymer produced with the Ziegler-Natta catalyst that does not substantially contain a heterogeneous bond. To ask.
The conversion of the ethylene content from mol% to wt% is performed using the following formula.
Ethylene content (% by weight) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100)} × 100
Here, X is the ethylene content in mol%.
Further, the ethylene content E (W) of the entire block copolymer is calculated from the ethylene contents E (A1), E (A2) and TREF of the components (A1) and (A2) measured above. The weight ratio W (A1) and W (A2) wt% is calculated by the following formula.
E (W) = {E (A1) × W (A1) + E (A2) × W (A2)} / 100 (wt%)

2. Propylene-ethylene block copolymer production method (1) Metallocene catalyst The method for producing a propylene-ethylene block copolymer according to the present invention requires the use of a metallocene catalyst.
In the propylene-ethylene block copolymer, when the molecular weight and crystallinity distribution are wide, it is well known to those skilled in the art that the stickiness and bleedout deteriorate, but the propylene-ethylene block copolymer used in the present invention. However, in order to suppress stickiness and bleed out, and to exhibit sufficient transparency in sheet molding, it is necessary to be polymerized using a metallocene catalyst that can narrow the molecular weight and crystallinity distribution, It is clear from the comparison of Examples and Comparative Examples described later that an excellent propylene-ethylene block copolymer according to the present invention cannot be obtained with a Ziegler-Natta catalyst.

The type of the metallocene-based catalyst is not particularly limited as long as it can produce a copolymer having the performance of the present invention, but in order to satisfy the requirements of the present invention, for example, the components (a ) And (b), and a metallocene catalyst composed of the component (c) used as necessary is preferably used.
Component (a): At least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1) Component (b): At least selected from the following (b-1) to (b-4) One solid component (b-1) A particulate carrier on which an organoaluminum compound is supported (b-2) An ionic compound capable of reacting with component (a) to convert component (a) into a cation Or a particulate carrier on which a Lewis acid is supported (b-3) a solid acid particulate (b-4) an ion-exchange layered silicate Component (c): an organoaluminum compound

(1-1) Component (a):
As the component (a), at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1) can be used.
_{Q (C 5 H 4 -aR 1} ) (C 5 H 4 -bR 2) MeXY (1)
[Wherein Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, Me represents a metal atom selected from titanium, zirconium, and hafnium, and X and Y represent hydrogen atoms. An atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, or a silicon-containing hydrocarbon group, which may be the same or different from each other. R ₁ and R _{2 each} represent hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, a silicon-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, an oxygen-containing hydrocarbon group, a boron-containing hydrocarbon group, or a phosphorus-containing hydrocarbon group. . a and b are the number of substituents. ]

Specifically, Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, for example, a divalent hydrocarbon group, a silylene group or an oligosilylene group, and a hydrocarbon group as a substituent. Examples thereof include a silylene group or an oligosilylene group, or a germylene group having a hydrocarbon group as a substituent. Among these, preferred is a silylene group having a divalent hydrocarbon group and a hydrocarbon group as substituents.
X and Y represent a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, or a silicon-containing hydrocarbon group. Among these, preferred are , Hydrogen, chlorine, methyl, isobutyl, phenyl, dimethylamide, diethylamide group and the like. X and Y may be the same or different independently.
Further, R ₁ and R ₂ are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group or phosphorus-containing hydrocarbon group. Represents. Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, and a butadienyl group. In addition, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group or phosphorus-containing hydrocarbon group include methoxy group, ethoxy group, phenoxy group, trimethylsilyl group. Typical examples include a group, diethylamino group, diphenylamino group, pyrazolyl group, indolyl group, dimethylphosphino group, diphenylphosphino group, diphenylboron group, dimethoxyboron group and the like. Among these, a hydrocarbon group having 1 to 20 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, and a butyl group are particularly preferable. By the way, adjacent R ₁ and R ₂ may combine to form a ring, on which a hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing You may have a substituent which consists of a hydrocarbon group, a boron containing hydrocarbon group, or a phosphorus containing hydrocarbon group.
Me is a metal atom selected from titanium, zirconium and hafnium, preferably zirconium and hafnium.

  Among the components (a) described above, preferred for the production of the propylene-ethylene block copolymer according to the present invention is a substituted cyclohexane crosslinked with a silylene group, a germylene group or an alkylene group having a hydrocarbon substituent. It is a transition metal compound comprising a ligand having a pentadienyl group, a substituted indenyl group, a substituted fluorenyl group, or a substituted azulenyl group, and particularly preferably 2 cross-linked by a silylene group having a hydrocarbon substituent or a germylene group , 4-position substituted indenyl group and 2,4-position substituted azulenyl group.

Non-limiting specific examples include dimethylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, diphenylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, dimethylsilylene bis (2-methyl). Benzoindenyl) zirconium dichloride, dimethylsilylenebis {2-isopropyl-4- (3,5-diisopropylphenyl) indenyl} zirconium dichloride, dimethylsilylenebis (2-propyl-4-phenanthrylindenyl) zirconium dichloride, dimethyl Silylenebis (2-methyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) azurenyl} zirconium dichloride, dimethylsilylenebi (2-Ethyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis (2-isopropyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis {2-ethyl-4- (2-fluorobiphenyl) azurenyl} zirconium Dichloride, dimethylsilylenebis {2-ethyl-4- (4-t-butyl-3-chlorophenyl) azurenyl} zirconium dichloride, and the like can be given.
Moreover, the compound which substituted the silylene group of the compound of these specific examples for the germylene group and the zirconium for hafnium is illustrated as a suitable compound.
In addition, since the catalyst component is not an important constituent requirement of the present invention, it avoids complicated listing and is limited to a representative example, but this does not limit the effective range of the present invention. It is self-evident.

(1-2) Component (b):
As the component (b), at least one solid component selected from the components (b-1) to (b-4) described above is used. Each of these components is a well-known thing, and can be used selecting it suitably from well-known techniques. Specific examples and manufacturing methods thereof are described in detail in JP-A No. 2002-284808, JP-A No. 2002-53609, JP-A No. 2002-69116, JP-A No. 2003-105015, and the like.
Here, as the particulate carrier used for the component (b-1) and the component (b-2), inorganic oxides such as silica, alumina, magnesia, silica alumina, silica magnesia, magnesium chloride, magnesium oxychloride, chloride Examples thereof include inorganic halides such as aluminum and lanthanum chloride, and porous organic carriers such as polypropylene, polyethylene, polystyrene, styrene divinyl benzene copolymer, and acrylic acid copolymer.

Further, as a non-limiting specific example of the component (b), as the component (b-1), a particulate carrier on which methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate tetraisobutyl and the like are supported As component (b-2), triphenylborane, tris (3,5-difluorophenyl) borane, tris (pentafluorophenyl) borane, triphenylcarbonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl Particulate carrier carrying anilinium tetrakis (pentafluorophenyl) borate, etc., component (b-3), alumina, silica alumina, magnesium chloride, etc., component (b-4), montmorillonite, zakonite, beidellite , Nontronic , Saponite, hectorite, stevensite, bentonite, smectite group such as taeniolite, vermiculite, and the like mica group. These may form a mixed layer.
Particularly preferred among the above components (b) is the ion-exchange layered silicate of component (b-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. It is an ion exchange layered silicate applied.

(1-3) Component (c):
Examples of organoaluminum compounds used as component (c) as needed are:
General formula: AlR _a X _3-a
(In the formula, R represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a hydrogen, halogen or alkoxy group, and a is a number of 0 <a ≦ 3.)
Or trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum and triisobutylaluminum, or halogen- or alkoxy-containing alkylaluminum such as diethylaluminum monochloride and diethylaluminum monomethoxide. In addition, aluminoxanes such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

(1-4) Formation of catalyst:
Component (a) is contacted with component (b) and, if necessary, component (c) to form a catalyst. Although the contact method is not specifically limited, Contact can be made in the following order. Moreover, this contact may be performed not only at the time of catalyst preparation but also at the time of prepolymerization with olefin or at the time of polymerization of olefin.
(I) The component (a) is contacted with the component (b).
(Ii) After contacting the component (a) and the component (b), the component (c) is added.
(Iii) After contacting the component (a) and the component (c), the component (b) is added.
(Iv) Component (b) and component (c) are contacted, and then component (a) is added.
(V) contacting the three components simultaneously.

(1-5) Component amount:
The amount of components (a), (b) and (c) used in the present invention is arbitrary. For example, the amount of component (a) used relative to component (b) is preferably in the range of 0.1 μmol to 1,000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of component (b). The amount of component (c) used relative to component (b) is preferably such that the amount of transition metal is 0.001 to 100 μmol, particularly preferably 0.005 to 50 μmol, relative to 1 g of component (b). Therefore, the amount of the component (c) to the component (a) is preferably in the range of 10 ⁻⁵ to 50, particularly preferably 10 ^{−4 to} 5 in terms of the molar ratio of the transition metal.

(1-6) Prepolymerization:
It is preferable that the catalyst according to the present invention is subjected to a prepolymerization treatment in which the olefin is contacted in advance and polymerized in a small amount. The olefin to be used is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, styrene and the like can be used. It is possible to use, and it is particularly preferable to use propylene.
The olefin can be supplied by any method such as a supply method for maintaining the olefin at a constant speed or in a constant pressure state, a combination thereof, or a stepwise change.
The prepolymerization temperature and time are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50 with respect to the component (b). After completion of the prepolymerization, the catalyst can be used as it is depending on the usage form of the catalyst, but may be dried if necessary.
Furthermore, a polymer such as polyethylene, polypropylene, or polystyrene, or an inorganic oxide solid such as silica or titania can be allowed to coexist during or after the contact of the above components.

(2) Production method (2-1) Sequential polymerization:
In producing the propylene-ethylene block polymer according to the present invention, the crystalline propylene-ethylene random copolymer component (A1) and the low crystalline or amorphous propylene-ethylene random copolymer component (A2) are combined. The sequential polymerization is necessary for the reason described above.
When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.
In the case of the batch method, it is possible to polymerize the component (A1) and the component (A2) individually using a single reactor by changing the polymerization conditions with time. As long as the effects of the present invention are not impaired, a plurality of reactors may be connected in parallel.
In the case of the continuous method, since it is necessary to individually polymerize the component (A1) and the component (A2), it is necessary to use a production facility in which two or more reactors are connected in series. As long as the above is not inhibited, a plurality of reactors may be connected in series and / or in parallel for each of the component (A1) and the component (A2).

(2-2) Polymerization process:
As the polymerization process (polymerization method), an arbitrary polymerization method such as a slurry method, a bulk method, or a gas phase method can be used. Although supercritical conditions can be used as intermediate conditions between the bulk method and the gas phase method, they are substantially the same as the gas phase method, and are therefore included in the gas phase method without particular distinction.
Since the low crystalline or amorphous propylene-ethylene random copolymer component (A2) is easily soluble in organic solvents such as hydrocarbons and liquefied propylene, a gas phase method may be used for the production of the component (A2). desirable.
In addition, for the production of the crystalline propylene-ethylene random copolymer component (A1), there is no particular problem no matter which process is used, but when producing the component (A1) having relatively low crystallinity. In order to avoid problems such as adhesion, it is desirable to use a vapor phase method.
Therefore, using a continuous method, the crystalline propylene-ethylene random copolymer component (A1) is first polymerized by a bulk method or a gas phase method, and subsequently, a low crystalline or amorphous propylene-ethylene random copolymer. It is most desirable to polymerize the elastomer component (A2) by a gas phase method.

(2-3) Other polymerization conditions:
The polymerization temperature can be used without any particular problem as long as it is within a commonly used temperature range. Specifically, a range of 0 ° C. to 200 ° C., more preferably 40 ° C. to 100 ° C. can be used.
In addition, the polymerization pressure varies depending on the process to be selected, but can be used without any particular problem as long as it is in a pressure range usually used. Specifically, a range of greater than 0 to 200 MPa, more preferably 0.1 MPa to 50 MPa can be used. At this time, an inert gas such as nitrogen may be allowed to coexist.
When the sequential polymerization of the component (A1) in the first step and the component (A2) in the second step is performed, it is desirable to add a polymerization inhibitor into the system in the second step. In the case of producing a propylene-ethylene block copolymer, if a polymerization inhibitor is added to a reactor that performs ethylene-propylene random copolymerization in the second step, the particle properties (fluidity, etc.) of the resulting powder, gel, etc. Can improve the product quality. Various technical studies have been made on this technique, and examples thereof include Japanese Patent Publication Nos. 63-54296, 7-25960, and 2003-2939. It is desirable to apply the method to the present invention.

3. Method for Controlling Constituent Requirements of Propylene-Ethylene Block Copolymer Each element of the propylene-ethylene block copolymer used in the method for forming a polypropylene-based high-frequency welder molded sheet of the present invention is controlled as follows. The propylene-ethylene block copolymer can be produced so as to satisfy the constituent requirements.

(1) Component (A1) For the crystalline propylene-ethylene random copolymer component (A1), the ethylene content [E (A1)] and the elution peak temperature [T (A1)] in the TREF elution curve are controlled. There is a need.
In the present invention, in order to control the ethylene content [E (A1)] within a predetermined range, the amount ratio of propylene and ethylene supplied to the polymerization tank in the first step may be appropriately adjusted. Although the relationship between the supply ratio and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, a component having the required ethylene content [E (A1)] by adjusting the supply ratio ( A1) can be produced. For example, when E (A1) is controlled to 0 to 7 wt%, the supply weight ratio of ethylene to propylene may be in the range of 0 to 0.3, preferably in the range of 0 to 0.2.
At this time, the component (A1) has a narrow crystallinity distribution, and T (A1) decreases as E (A1) increases.
Therefore, in order for T (A1) to satisfy the scope of the present invention, E (A1) and the relationship between these are grasped and adjusted to take the target range.

(2) Component (A2) For the low crystalline or amorphous propylene-ethylene random copolymer component (A2), the ethylene content [E (A2)] and the elution peak temperature [T (A2) in the TREF elution curve )] Must be controlled.
In the present invention, in order to control the ethylene content [E (A2)] to a predetermined range, the ratio of ethylene supply to propylene in the second step may be controlled as in E (A1).
For example, when E (A2) is controlled to 5 to 20 wt%, the supply weight ratio of ethylene to propylene may be in the range of 0.01 to 5, preferably in the range of 0.05 to 2. At this time, although the crystallinity distribution of the component (A2) is slightly increased with the increase of the ethylene content, T (A2) is decreased with the increase of E (A2) as with the component (A1). .
Therefore, in order for T (A2) to satisfy the scope of the present invention, the relationship between E (A2) and T (A2) is grasped, and E (A2) is controlled to be within a predetermined range. Good.

(3) About W (A1) and W (A2) The amount [W (A1)] of component (A1) and the amount [W (A2)] of component (A2) are the first steps for producing component (A1). It is possible to control by changing the ratio of the production amount of the component and the production amount of the component (A2). For example, in order to increase W (A1) and reduce W (A2), it is only necessary to reduce the production amount of the second step while maintaining the production amount of the first step. It can be easily controlled by shortening, lowering the polymerization temperature, or increasing the amount of the polymerization inhibitor. The reverse is also true.
When actually setting the conditions, it is necessary to consider the activity decay. That is, in the range of the ethylene content [E (A1)] and [E (A2)] carried out in the present invention, when the ethylene supply ratio to propylene is generally increased in order to increase the ethylene content, the polymerization activity is increased. Tends to increase, and at the same time, the activity decay tends to increase. Therefore, in order to maintain the activity of the second step, it is necessary to suppress the polymerization activity of the first step. Specifically, in the first step, the production amount W (A1) is lowered, and if necessary, Lower the polymerization temperature and / or shorten the polymerization time (residence time), or increase the ethylene content E (A2) and increase the production W (A2) in the second step, and if necessary, the polymerization temperature The conditions may be set in such a way as to increase the polymerization time and / or increase the polymerization time (residence time).

(4) Glass transition temperature (Tg) In the propylene-ethylene block copolymer used in the present invention, the glass transition temperature (Tg) described above needs to have a single peak. In order for Tg to have a single peak, the difference between the ethylene content [E (A1)] in component (A1) and the ethylene content [E (A2)] in component (A2) [E (gap) That is, [E (A2) -E (A1)] is set to 20 wt% or less, preferably 18 wt% or less, more preferably 16 wt% or less, and in the actual measurement, E (gap ) Should be reduced.
Depending on the ethylene content [E (A1)] of the crystalline copolymer component (A1), the ethylene content [E (A2)] of the low crystalline or amorphous copolymer component (A2) is appropriate. By setting the supply weight ratio of ethylene to propylene during the polymerization of component (A2) so as to fall within the range, a polymer having a predetermined E (gap) can be obtained.
The Tg of the block copolymer that does not take a phase separation structure as in the present invention is the ethylene content [E (A1)] in the component (A1) and the ethylene content [E (A2) in the component (A2). )], And the amount ratio of both components. In the present invention, the amount of the component (A2) is 5 to 70 wt%, but in this range, Tg is more strongly affected by the ethylene content [E (A2)] in the component (A2).
That is, Tg reflects the glass transition of the amorphous part, but in the block copolymer component (A) according to the present invention, the component (A1) has crystallinity and relatively few amorphous parts. On the other hand, the component (A2) is low crystalline or amorphous, and most of it is an amorphous part.
Therefore, the value of Tg is controlled almost by the ethylene content [E (A2)] in the component (A2), and the control method of E (A2) is as described above.

(5) Melt Flow Rate (MFR) In the propylene-ethylene block copolymer (A) according to the present invention, in order to maintain transparency, the crystalline copolymer component (A1) and a low crystalline or non-crystalline Since it is essential that the crystalline copolymer elastomer component (A2) is compatible, the viscosity of the component (A1): [η] A1, the viscosity of the component (A2): [η] A2, propylene- Between the viscosity of the entire ethylene block copolymer (A): [η] W, the apparent viscosity mixing rule is generally established. That is,
Log [η] W = {W (A1) × Log [η] A1 + W (A2) × Log [η] A2} / 100
Is generally established.
In general, since there is a certain correlation between MFR and [η], first, [η] A2, W (A1), and W (A2) should be set from the viewpoint of flexibility and heat resistance. For example, the MFR can be freely controlled by changing [η] A1 according to the above formula.

4). Additional ingredients (additives)
The polypropylene sheet used in the present invention may be blended with a soft polymer such as an ethylene-α-olefin copolymer or a styrene-butadiene copolymer component for the purpose of improving flexibility and impact resistance. good. The standard of the amount to be blended is generally 0 to 30 wt%, and when it exceeds 30 wt%, the transparency tends to deteriorate.
The ethylene-α-olefin copolymer is a copolymer of ethylene and propylene, butene, hexene, vinyl acetate or the like, and preferably has an ethylene content of 60 to 95 wt%. When the ethylene content exceeds 95 wt%, the effect of improving the flexibility and impact resistance is not easily observed. On the other hand, when the ethylene content is less than 60 wt%, the transparency tends to deteriorate.
As the styrene-butadiene copolymer, a hydrogenated styrene-based thermoplastic elastomer or the like is preferable because it has a good effect of improving flexibility and impact resistance.

  In the polypropylene sheet used in the present invention, a nucleating agent, an antioxidant, a neutralizing agent, a light stabilizer, and an ultraviolet absorber, which are used as known compounding agents for polyolefin resins, as long as the effects of the present invention are not impaired. Various additives such as an anti-blocking agent, a lubricant, an antistatic agent, a metal deactivator, a peroxide, a filler, an antibacterial and antifungal agent, and a fluorescent brightening agent may be blended. The amount of these additives is generally 0.0001 to 3% by weight, preferably 0.001 to 1% by weight.

5). Polypropylene Sheet (1) Manufacturing Method of Sheet The polypropylene sheet used in the present invention is blended with the above-mentioned propylene-ethylene block copolymer (A), if necessary, with the above additional components (additives). The propylene-based resin composition can be obtained by generally used extrusion sheet molding, film molding, calendar molding, injection molding, press molding, or the like. Of these, extrusion sheet molding is the most common.

As extrusion sheet forming, the sheet is extruded from a coat solder die through a single-screw or twin-screw extruder. Then, the extruded sheet is cooled and solidified by pressing with an air knife, an air chamber, a hard rubber roll, a steel belt, and a metal roll on the surface of the metal roll in which cooling water and oil are circulated. The Further, both sides of the sheet can be cooled and solidified by being sandwiched between steel belts.
Among such sheet cooling methods, the method using metal rolls and / or steel belts on both sides of the sheet is the most preferable method because a sheet surface with less surface irregularities, that is, a sheet excellent in transparency can be obtained. It is.

(2) Configuration of Polypropylene Sheet The polypropylene sheet used in the present invention may be a single layer or a multilayer sheet with other resin layers.
The multilayer sheet is a flexible elastomer layer, a gas barrier, using an extruder equipped with a plurality of dies, and using a feed block or multi-manifold so that the layer made of the propylene-ethylene block copolymer becomes the outermost layer. A resin layer, an adhesive resin layer, a recycled resin layer, a candle resin layer, and the like are laminated.

The polypropylene sheet used in the present invention preferably has a thickness of 10 to 250 μm. If the thickness is less than 10 μm, the strength is insufficient, whereas if the thickness exceeds 250 μm, the flexibility may be insufficient.
In addition, the polypropylene sheet used in the present invention includes, as other sheets, for example, a soft polymer sheet such as an ethylene polymer and a styrene polymer, a cross sheet of synthetic fibers such as PET and PP, and a non-woven fabric. It can also be used as a composite sheet such as paper or foam.

6). Molding Method of Polypropylene High Frequency Welder Molded Sheet The polypropylene high frequency welder molded sheet according to the present invention can be obtained by the following molding method.
That is, for example, when the polypropylene-based high-frequency welder molding sheet is a single layer, the high-frequency welder molding machine generally used for bonding the resin sheet is used after the polypropylene-based sheets are stacked. Can be obtained. Further, when the polypropylene sheet is a multilayer sheet, after superposing the outermost surfaces of the polypropylene sheet having the layer made of the propylene-ethylene block copolymer as the outermost surface layer, or between the end faces of the sheet After combining, as in the case of a single layer, it can be obtained by using a high-frequency welder molding machine generally used for bonding resin sheets.
In this specification, the high-frequency welder processing is a processing method using high-frequency heating, and the high-frequency heating is a material loss caused by applying a high frequency to the dielectric of the material, and heat generated by that. Say. The high frequency welder or the high frequency welder processability (formability) refers to the ease of welding by the high frequency welder. The welding is due to a high-frequency dielectric heating phenomenon that generates heat when a high-frequency electric field is applied to the plastic, and the product of the dielectric constant (ε) and the dielectric loss tangent (tan δ) is a measure of the amount of generated heat. It is preferable to use a high frequency welder molding machine for welding with a mold having a temperature of 40 ° C. or less, and more preferably 35 ° C. or less.
Specific examples of the high-frequency welder molding machine include YPO-5, YC-7000F, YO-5A, and YO-5AN manufactured by Yamamoto Vinita Co., Ltd.

At this time, in the present invention, high frequency welder molding is performed under the condition that the anode current [unit: ampere (A)] satisfies the following expression (1).
1.0 ≧ Anode current ≧ 0.0028 × Sheet thickness (μm) +0.1271 (1) Formula If the anode current greatly exceeds 1.0 ampere, an overcurrent occurs and sparks are generated and molding is possible. On the other hand, if it is significantly less than {0.0028 × sheet thickness (μm) +0.1271} ampere, there is a risk of poor adhesion.

7). Use of polypropylene-based high-frequency welder molded sheet The polypropylene-based high-frequency welder molded sheet obtained by the molding method of the present invention has excellent transparency, high heat resistance, excellent flexibility, high-frequency welder moldability, food, It can be used as various packaging materials such as daily necessities and industrial materials.
Examples of such applications include stationery such as file holders, factory dividers that generate heat by taking advantage of its heat resistance, machine partition sheets, flexible containers that package hot products, and the influence of solar heat outdoors. Can be used as a cover or curing sheet.
In addition, the polypropylene-based high-frequency welder molded sheet can be processed into a composite sheet with a fiber cloth. Further, a high-strength sheet can be obtained and used as an industrial material such as a tent sheet or a curing sheet.

In the following, in order to describe the present invention more specifically and clearly, the present invention will be described in comparison with Examples and Comparative Examples, and the rationality and significance of the requirements of the configuration of the present invention will be demonstrated.
The evaluation methods and resins used in the examples and comparative examples are as follows.

1. Method for measuring physical properties of propylene-ethylene block copolymer (1) Melt flow rate (MFR):
According to JIS K7210 A method condition M, it measured on condition of the following.
Test temperature: 230 ° C
Nominal load: 2.16kg
Die shape: 2.095mm diameter, 8.00mm length

(2) TREF:
A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) at 140 ° C. to prepare a solution. After this is introduced into a TREF column at 140 ° C., it is cooled to 100 ° C. at a temperature decreasing rate of 8 ° C./min, subsequently cooled to −15 ° C. at a temperature decreasing rate of 4 ° C./min, and held for 60 minutes. Thereafter, o-dichlorobenzene (containing 0.5 mg / ml BHT) as a solvent is caused to flow through the column at a flow rate of 1 ml / min, and components dissolved in o-dichlorobenzene at −15 ° C. in the TREF column. Elution is performed for 10 minutes, and then the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.

〔apparatus〕:
(TREF part):
TREF column: 4.3 mmφ × 150 mm stainless steel column Column packing material: 100 μm, surface inactive glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation, digital program controller KP1000 (valve oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve

(Sample injection part):
Injection method: Loop injection method Injection amount: Loop size, 0.1ml
Inlet heating method: Aluminum heat block Measurement temperature: 140 ° C
(Detection unit):
Detector: Fixed wavelength infrared detector, MIRAN 1A manufactured by FOXBORO
Detection wavelength: 3.42 μm
High-temperature flow cell: LC-IR micro flow cell, optical path length 1.5 mm, window shape 2φ × 4 mm oval, synthetic sapphire window Measurement temperature: 140 ° C.
(Pump part):
Liquid feed pump: SSC-3461 pump manufactured by Senshu Kagaku

〔Measurement condition〕:
Solvent: o-dichlorobenzene (containing 0.5 mg / ml BHT)
Sample concentration: 5 mg / ml
Sample injection volume: 0.1 ml
Solvent flow rate: 1 ml / min

(3) Solid viscoelasticity measurement:
The sample used was cut into a strip of 10 mm width × 18 mm length × 2 mm thickness from a 2 mm thick sheet injection molded under the following conditions. The apparatus used was ARES manufactured by Rheometric Scientific. The frequency is 1 Hz. The measurement temperature was raised stepwise from −60 ° C., and the measurement was performed until the sample melted and became impossible to measure. The strain was performed in the range of 0.1 to 0.5%.

[Preparation of specimen]:
Standard number: JIS K7152 (ISO294-1)
Molding machine: TU-15 injection molding machine manufactured by Toyo Machine Metal Co., Ltd. Molding machine set temperature: 80, 80, 160, 200, 200, 200 ° C. from below the hopper
Mold temperature: 40 ℃
Injection speed: 200 mm / sec (speed in the mold cavity)
Injection pressure: 800 kgf / cm ²
Holding pressure: 800 kgf / cm ²
Holding time: 40 seconds Mold shape: Flat plate (thickness 2mm, width 30mm, length 90mm)

(4) Melting peak temperature (Tm) and melting enthalpy (dHm) by DSC:
Using a Seiko DSC, take 5.0 mg of sample, hold at 200 ° C. for 5 minutes, crystallize to 40 ° C. at a rate of temperature decrease of 10 ° C./min, and further melt at a rate of temperature increase of 10 ° C./min. The melting peak temperature was Tm (unit: ° C.). DHm was determined from the area of the endothermic curve at the time of temperature increase.

(5) Calculation of ethylene content:
Calculation was performed by the method described in detail in the present specification.

(6) Molecular weight (Mw, Mn):
It measured with the following method by the gel permeation chromatography (GPC).
Conversion from the retention volume to the molecular weight is performed using a standard curve prepared in advance by standard polystyrene. The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is prepared by injecting 0.2 ml of a solution dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) so that each is 0.5 mg / ml. The calibration curve uses a cubic equation obtained by approximation by the least square method. The following numerical values are used for [η] = K × M ^α in the viscosity formula used for conversion to molecular weight.
PS: K = 1.38 × 10 ⁻⁴ α = 0.7
PE: K = 3.92 × 10 ⁻⁴ α = 0.733
PP: K = 1.03 × 10 ⁻⁴ α = 0.78
The measurement conditions for GPC are as follows.
Apparatus: GPC (ALC / GPC 150C) manufactured by WATERS
Detector: MIRAN 1A IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
Mobile phase solvent: o-dichlorobenzene Measurement temperature: 140 ° C
Flow rate: 1.0 ml / min
Injection volume: 0.2ml
Sample preparation: Prepare a 1 mg / ml solution using o-dichlorobenzene (containing 0.5 mg / ml BHT) and dissolve it at 140 ° C. for about 1 hour.
The amount of the component having a molecular weight of 5,000 or less was also determined from a plot of the elution ratio against the molecular weight obtained by GPC measurement.

[Production Example PP-1]:
[Polymerization Production Example A-1]
1. Preparation of prepolymerization catalyst (chemical treatment of silicate):
To a 10-liter glass separable flask with a stirring blade, 3.75 liters of distilled water was added slowly followed by 2.5 kg of concentrated sulfuric acid (96%). At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm, particle size distribution = 10-60 μm) was dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered.
This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.

(Drying silicate):
The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical, inner diameter 50 mm, heating zone 550 mm (electric furnace)
Rotating speed with lifting blade: 2rpm
Tilt angle: 20/520
Silicate supply rate: 2.5 g / min Gas flow rate: Nitrogen 96 liters / hour Countercurrent drying temperature: 200 ° C. (powder temperature)

(Catalyst preparation):
An autoclave with an internal volume of 16 liters equipped with a stirring and temperature control device was thoroughly replaced with nitrogen. To this, 200 g of dry silicate was introduced, 1,160 ml of mixed heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added and stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane to prepare 2,000 ml of silicate slurry.
Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 ML) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. In parallel, 270 ml of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium and 2,180 mg (0.3 mM) of mixed heptane Then, 33.1 ml of a heptane solution of triisobutylaluminum (0.71 M) was added, and the mixture reacted at room temperature for 1 hour was added to the silicate slurry. After stirring for 1 hour, 5,000 ml was added with mixed heptane. Prepared.

(Prepolymerization / washing):
Subsequently, the temperature in the tank was raised by 40 ° C., and when the temperature was stabilized, propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the residual monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted to 2,400 ml. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 ML) and 5600 ml of mixed heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then 5600 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the final supernatant was performed, the concentration of the organoaluminum component was 1.23 mmol / liter, the Zr concentration was 8.6 × 10 −6 g / L, and the abundance in the supernatant relative to the charged amount was It was 0.016%. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 ML) was added, followed by drying at 45 ° C. under reduced pressure. A prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.

2. First Step In the first step, propylene-ethylene random copolymerization was carried out using a liquid phase polymerization tank with a stirrer having an internal volume of 0.4 m ³ . Liquefied propylene, liquefied ethylene, and triisobutylaluminum were continuously fed at 90 kg / hour, 4.2 kg / hour, and 21.2 g / hour, respectively. The hydrogen supply amount was adjusted so that the MFR in the first step became a target value.
Further, the above prepolymerized catalyst was supplied as a catalyst (excluding the weight of the prepolymerized polymer) so as to be 6.9 g / hour. The polymerization tank was cooled so that the polymerization temperature was 45 ° C.
When the propylene-ethylene random copolymer obtained in the first step was analyzed, BD (bulk density) was 0.46 g / cc, MFR was 2.0 g / 10 min, and ethylene content was 3.7 wt%. .

3. Second Step In the second step, propylene-ethylene random copolymerization was performed using a stirred gas phase polymerization tank having an internal volume of 0.5 m ³ . The slurry containing polymer particles was continuously extracted from the liquid phase polymerization tank in the first step, and after liquefied propylene was flushed, the pressure was increased with nitrogen and continuously supplied to the gas phase polymerization tank.
The polymerization tank was controlled so that the temperature was 80 ° C. and the total partial pressure of propylene, ethylene, and hydrogen was 1.5 MPa. At that time, the concentration of propylene, ethylene and hydrogen in the total partial pressure of propylene, ethylene and hydrogen was controlled to be 66.97 vol%, 32.99 vol% and 420 volppm, respectively.
Furthermore, ethanol was supplied to the gas phase polymerization tank as an activity inhibitor. The supply amount of ethanol was set to 0.3 mol / mol with respect to aluminum in TIBA supplied along with the polymer particles supplied to the gas phase polymerization tank.
When the propylene-ethylene block copolymer thus obtained was analyzed, the activity was 8.7 kg / g-catalyst, the BD was 0.41 g / cc, the MFR was 2.0 g / 10 min, and the ethylene content was 8.7 wt. %Met.

(Granulation):
The following antioxidant, neutralizing agent and lubricant were added to the block copolymer powder obtained in Polymerization Production Example A-1 by a blender, and the mixture was sufficiently stirred and mixed.
Antioxidant: Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane (manufactured by Ciba Specialty Chemicals, Inc., Irganox 1010) 0.05 Parts by weight, tris (2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Specialty Chemicals Co., Ltd. Irgafos 168) 0.10 parts by weight Neutralizer: calcium stearate (manufactured by Nippon Oil & Fats Co., Ltd.) Stearate G) 0.05 part by weight Lubricant: Oleic acid amide (Nippon Seika Co., Ltd. Neutron) 0.05 part by weight

  The copolymer powder to which the additive has been added is high-speed mixed at 750 rpm for 1 minute at room temperature with a Henschel mixer. The melted resin is melt kneaded at an extruder temperature of 190 ° C., and the molten resin extruded from the strand die is taken out while being cooled and solidified in a cooling water tank, and the strand is cut into a length of about 3 mm and a diameter of about 2 mm using a strand cutter. A raw material pellet (PP-1) of a propylene-ethylene block copolymer (A) was obtained.

(analysis):
Using the obtained PP-1 pellets, TREF, ethylene content, DSC, GPC, and solid viscoelasticity were measured. Table 4 shows each data obtained by the measurement.
From the measurement results obtained, it can be said that PP-1 satisfies all the requirements as the component (A).
Here, in order to show the position of each parameter in the TREF measurement result, an elution curve is illustrated in FIG. In order to show the position of each parameter in the solid viscoelasticity measurement results, FIG. 2 illustrates changes in storage elastic modulus G ′, loss elastic modulus G ″ and loss tangent tan δ with respect to temperature.

[Production Example PP-1B]: [Production Example PP-2 to 3]:
[Polymerization Production Examples A-2 to 3]
In the same manner as in Polymerization Production Example A-1, a propylene-ethylene block copolymer was produced by changing the polymerization conditions. The polymerization conditions and polymerization results are shown in Table 3.
Using the obtained polymer powder, PP-2 to 3 were obtained by the same additive formulation and granulation conditions as in Production Example PP-1. Various analysis results are shown in Table 4.

[Production Example PP-4]:
[Polymerization Production Example A-4]
In Polymerization Production Example A-1, polymerization was carried out in the same manner as in Polymerization Production Example A-1, except that only the first step was performed without performing the second step, and the propylene-ethylene random copolymer was Manufactured. The polymerization conditions and polymerization results are shown in Table 3.
Using the obtained polymer powder, PP-4 was obtained by the same additive formulation and granulation conditions as in Production Example PP-1. Various analysis results are shown in Table 4.

[Production Example PP-5]:
[Polymerization Production Example A-5]
(Preparation of solid catalyst component):
2,000 milliliters of dehydrated and deoxygenated n-heptane was introduced into a flask thoroughly purged with nitrogen, and then 2.6 mol of MgCl ₂ and 5.2 mol of Ti (On-C ₄ H ₉ ) ₄ were introduced. The mixture was introduced and reacted at 95 ° C. for 2 hours. After completion of the reaction, the temperature was lowered to 40 ° C., and then 320 ml of methylhydropolysiloxane (20 centistokes) was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane.
Next, 4,000 milliliters of n-heptane purified in the same manner as described above was introduced into a sufficiently nitrogen-substituted flask, and 1.46 mol of the solid component synthesized above was introduced in terms of Mg atoms. Next, 25 ml of n-heptane was mixed with 2.62 mol of SiCl ₄ , introduced into the flask at 30 ° C. for 30 minutes, and reacted at 70 ° C. for 3 hours. After completion of the reaction, washing with n-heptane was performed.
Next, 0.15 mol of phthalic acid chloride was mixed with 25 ml of n-heptane, introduced into the flask at 70 ° C. for 30 minutes, and reacted at 90 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 11.4 mol of TiCl ₄ was introduced and reacted at 110 ° C. for 3 hours. After completion of the reaction, the solid component (A1) was obtained by washing with n-heptane. The titanium content of this solid component was 2.0 wt%.
Next, the autoclave having an internal volume of 16 liters having a stirring and temperature control device was sufficiently replaced with nitrogen, and 5,000 milliliters of n-heptane purified in the same manner as above was introduced into the solid component (A1 ) Was introduced, and 0.875 mol of SiCl ₄ was introduced and reacted at 90 ° C. for 2 hours. After completion of the reaction, further (CH ₂ ═CH) Si (CH ₃ ) ₃ 0.15 mol, (t-C ₄ H ₉ ) (CH ₃ ) Si (OCH ₃ ) ₂ 0.075 mol and Al (C ₂ H ₅ ) ₃ 0.4 mol was sequentially introduced and contacted at 30 ° C. for 2 hours. After completion of the contact, the solid catalyst component (A) mainly composed of magnesium chloride was obtained by thoroughly washing with n-heptane. The titanium content of this product was 1.8 wt%.

(Preliminary polymerization):
An autoclave with an internal volume of 16 liters equipped with a stirring and temperature control device was sufficiently replaced with nitrogen. Here, 100 g of the n-heptane slurry of the solid catalyst component (A) prepared above was introduced as the solid catalyst component (A), and n-heptane was further introduced to adjust the liquid level to 5000 ml.
Next, adjust the chamber temperature to 15 ° C., was 0.1mol added triethylaluminum · n-heptane solution (10 wt%) as _{Al (C 2 H 5) 3} . Thereafter, prepolymerization was performed by supplying propylene at a rate of 50 g / hour for 2 hours. After completion of the prepolymerization, the residual monomer was purged and the solid catalyst was thoroughly washed with n-heptane. After the washing, drying under reduced pressure was performed to obtain a prepolymerized catalyst. The prepolymerized catalyst contained 2.0 g of polypropylene per 1 g of the catalyst.
Polymerization Production Example A-, except that the prepolymerized catalyst thus obtained was used, and triethylaluminum was continuously fed at 10 g / hour instead of triisobutylaluminum, and the polymerization conditions shown in Table 3 were used. In the same manner as in No. 1, a propylene-ethylene block copolymer was produced. The polymerization results are shown in Table 3.
Using the obtained polymer powder, PP-5 was obtained by the same additive formulation and granulation conditions as in Production Example PP-1. Various analysis results are shown in Table 4.

[Example 1]
Using the obtained PP-1 pellets as a raw material, a polypropylene sheet was obtained under the following sheet production conditions. Table 5 shows the evaluation results of the obtained sheet.
The polypropylene sheet according to the present invention was excellent in flexibility, transparency and heat resistance, and the polypropylene high frequency welder molded sheet obtained by the molding method of the present invention was excellent in adhesiveness.

[Production of sheet]:
(Sheet manufacturing conditions):
PP-1 was melt-extruded from a T-die at a molding temperature of 220 ° C. using a 65Φ mm single-screw extruder, and was cooled and solidified by being sandwiched between a 15 ° C. cooling roll and a metal belt to obtain a sheet having a thickness of 0.2 mm.

[Evaluation of sheet properties]
(1) Tensile modulus (unit: MPa):
Under the following conditions, the sheet flow direction (MD) and the orthogonal direction (TD) were measured, and used as a measure of sheet flexibility. The calculation method of the tensile elastic modulus conformed to JIS K7127-1999.
Sample length: 150mm
Sample width: 15mm
Distance between chucks: 100mm
Crosshead speed: 1mm / min

(2) Haze (unit:%):
The transparency of the obtained sheet was evaluated by haze measurement. The measuring method was based on JIS K7136-2000.

(3) Heat resistance:
The obtained sheet | seat was preserve | saved for 30 minutes in 90 degreeC oven, and the sheet | seat state was observed.
The evaluation criteria for heat resistance are as follows.
X: Significant dimensional change occurred in the sheet, and gloss on the sheet surface was remarkably lost.
○: Almost no dimensional change occurred, but the gloss of the sheet surface was lost.
(Double-circle): A dimension and the surface state did not change with oven preservation | save.

(4) High frequency welder processability:
The obtained sheet was subjected to a high-frequency welder molding machine with the following equipment and conditions, and the adhesion was evaluated by the anode current shown in Table 5.
The evaluation criteria for adhesiveness are as follows.
X: Not bonded.
○: It peels off when it is adhered and peeled off by hand.
A: Adhered completely, and the sheet breaks when it is peeled off by hand.
Evaluation equipment: High frequency welder molding machine YPO-5 (manufactured by Yamamoto Vinita Co., Ltd.)
Welding time: 1 second Cooling time: 2 seconds

[Example 2]
A polypropylene sheet was obtained in the same manner as in Example 1 except that the sheet thickness of Example 1 was changed to 0.03 mm. Table 5 shows the evaluation results of the obtained sheet.
The polypropylene sheet according to the present invention was excellent in flexibility, transparency and heat resistance, and the polypropylene high frequency welder molded sheet obtained by the molding method of the present invention was excellent in adhesiveness.

[Example 3]
A polypropylene sheet was obtained in the same manner as in Example 1 except that PP-1 in Example 1 was replaced with PP-2. Table 5 shows the evaluation results of the obtained sheet.
The polypropylene sheet according to the present invention was excellent in flexibility, transparency and heat resistance, and the polypropylene high frequency welder molded sheet obtained by the molding method of the present invention was excellent in adhesiveness.

[Example 4]
A polypropylene sheet was obtained in the same manner as in Example 1 except that the sheet thickness of Example 1 was changed to 0.1 mm.
Table 5 shows the evaluation results of the obtained sheet.
The polypropylene sheet according to the present invention was excellent in flexibility, transparency and heat resistance, and the polypropylene high frequency welder molded sheet obtained by the molding method of the present invention was excellent in adhesiveness.

[Comparative Example 1]
A polypropylene sheet was obtained in the same manner as in Example 1 except that PP-1 in Example 1 was replaced with PP-3. The obtained sheet evaluation results are shown in Table 5.
Since one having a plurality of tan δ peaks different from the propylene-ethylene block copolymer used in the present invention was used, the transparency was inferior.

[Comparative Example 2]
A polypropylene sheet was obtained in the same manner as in Example 1 except that PP-1 in Example 1 was replaced with PP-4. Table 5 shows the evaluation results of the obtained sheet.
Since a random copolymer different from the propylene-ethylene block copolymer used in the present invention is used, the flexibility is inferior, and even if high frequency welder molding is performed by an anode current within the scope of the present invention. The adhesive property of the obtained polypropylene-based high-frequency welder molded sheet was not sufficient.

[Comparative Example 3]
A polypropylene sheet was obtained in the same manner as in Example 1 except that PP-1 in Example 1 was replaced with PP-5. Table 5 shows the evaluation results of the obtained sheet.
Since what was polymerized by the Ziegler Natta catalyst different from the metallocene catalyst used in order to obtain the propylene-ethylene block copolymer used for this invention was used, the obtained polypropylene-type sheet became inferior in heat resistance.

[Comparative Example 4]
Evaluation was carried out in the same manner as in Example 1 except that PP-1 in Example 1 was replaced with an ethylene-vinyl acetate copolymer (Novatech EVA LV450: manufactured by Nippon Polyethylene Co., Ltd.) having a vinyl acetate content of 15 wt%. Is shown in Table 5.
In high-frequency welder molding, it has a sufficient adhesive force. However, when such a copolymer is used, the heat resistance of the obtained sheet is remarkably lowered, and the quality of the product is remarkably lowered.

[Comparative Examples 5 and 6]
The same operation as in Example 1 was performed except that the thickness of Example 1 was changed to the thickness shown in Table 5 and the anode current of the high-frequency welder molding was changed to the current shown in Table 5. The evaluation results are shown in Table 5.
Adhesiveness was inferior due to insufficient anode current in high frequency welder molding.

[Comparative Example 7]
The same operation as in Example 1 was performed except that the thickness of Example 1 was changed to the thickness shown in Table 5 and the anode current of the high-frequency welder molding was changed to the current shown in Table 5. The evaluation results are shown in Table 5.
Since the anode current in the high frequency welder molding was an overcurrent, sparking occurred and bonding was impossible.

[Example 5]
PP-1 of Example 1 was extruded from a die of an extrusion laminator and laminated onto a PP fiber cloth sheet. The laminate substrate was inverted, PP-1 was extruded in the same manner on the opposite side, and laminated with a laminating machine to obtain a laminated sheet.
When this laminated sheet was applied to a welder molding machine and bonded in the same manner as in Example 1, a very strong bond was obtained, and a high-strength polypropylene high-frequency welder molded sheet was obtained.

  The polypropylene-based high-frequency welder molded sheet obtained by the molding method of the present invention has excellent transparency, high heat resistance, excellent flexibility, and excellent high-frequency welder moldability, such as food, daily necessities, industrial materials, etc. Can be used as various packaging materials, for example, stationery such as file holders, factory partitions that generate heat by taking advantage of its heat resistance, machine partition sheets, flexible containers for packaging products with heat, the influence of solar heat outdoors It can be used as a cover or a curing sheet when receiving the product, and has high industrial applicability.

Claims (4)

After superposing polypropylene sheets using propylene-ethylene block copolymers satisfying the conditions (Ai) to (A-iii), or after aligning the end faces of the sheets, using a high frequency welder A method for molding a polypropylene-based high-frequency welder molded sheet, wherein the anode current [unit: ampere (A)] is molded under a condition satisfying the following formula (1).
1.0 ≧ anode current ≧ 0.0028 × sheet thickness (μm) +0.1271 (1) Formula (A-i) In the first step, 0.3 to 7% by weight using a metallocene catalyst 30 to 95% by weight of propylene-ethylene random copolymer component (A1) containing ethylene in the second step, and propylene-ethylene random containing ethylene in the second step in an amount 3 to 20% by weight greater than the ethylene content of component (A1) It is a propylene-ethylene block copolymer formed by successively polymerizing 5 to 70% by weight of the copolymer component (A2).
(A-ii) Melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is in the range of 0.1 to 30 g / 10 minutes.
(A-iii) The temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA) has a single peak at 0 ° C. or lower.   The method for forming a polypropylene-based high-frequency welder-formed sheet according to claim 1, wherein the polypropylene-based sheet is a multilayer sheet having a layer using a propylene-ethylene block copolymer as an outermost surface layer.   The method for molding a polypropylene-based high-frequency welder-molded sheet according to claim 1 or 2, wherein the polypropylene-based sheet has a thickness of 10 to 250 µm.   A molded product formed by the method for forming a polypropylene-based high-frequency welder molded sheet according to any one of claims 1 to 3.

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