JP4741818B2 - Polypropylene nonwoven fabric molding - Google Patents

Description

  The present invention relates to a polypropylene-based nonwoven fabric molded product and its use, and more particularly, to a polypropylene-based nonwoven fabric molded product having high strength and excellent ultrasonic fusion properties and its use.

  Propylene-based resins such as polypropylene are excellent in moldability and rigidity, and are also excellent in recyclability and heat resistance, so they are variously molded and processed into food containers, like other resins such as polyvinyl chloride and polystyrene. Widely used in various applications such as food packaging materials, medical instruments, medical containers, and packaging films.

In particular, non-woven fabric using polypropylene is used for various purposes, such as surgical clothes, paper diapers, sanitary items, medical and sanitary materials, packaging materials, industrial materials such as oil adsorbents, clothing materials, and cleaning. It is used in food-related fields such as timber, daily miscellaneous goods such as garbage bags, and food packaging materials.
Usually, since a nonwoven fabric made of polypropylene generally requires flexibility, a random copolymer obtained by copolymerizing a small amount of α-olefin with propylene is used. For example, a fiber made of an ethylene-propylene copolymer having a softening point of 132 ° C. or less and having excellent heat roll processability made of an ethylene-propylene random copolymer containing a predetermined amount of ethylene is disclosed ( For example, see Patent Document 1.) However, a nonwoven fabric using this fiber is poor in flexibility, and has a drawback that the temperature range that can be processed into a nonwoven fabric having strength and flexibility suitable for practical use is extremely narrow. Furthermore, for example, a propylene-ethylene copolymer comprising 0.01 to 15 mol% of ethylene units and 99.99 to 85 mol of propylene units, having a chain structure based on a specific nuclear magnetic resonance spectrum, and having a weight average molecular weight (Mw) Is 50,000 to 1,500,000, and the weight average molecular weight (Mw) number average molecular weight (Mn) ratio (Mw / Mn) is 1.2 to 3.8 propylene-ethylene copolymer A fiber molded using the coalescence as at least one raw material and a fiber molded body using the same are disclosed (for example, see Patent Document 2).

In order to form a final product such as a mask or a sanitary material from a nonwoven fabric, it is common to bond the nonwoven fabric by hot melt adhesive or heat processing. However, in such secondary processing, there are problems that the molding time becomes long and the energy cost increases, and that the use of an adhesive increases the cost and the environmental load.
As a new technique for secondary processing, an ultrasonic fusion method is attracting attention. The principle of ultrasonic fusion is that ultrasonic waves are applied to the nonwoven fabric and fused by vibration frictional heat, so that shortening of molding time and cost reduction are expected. However, sufficient adhesive strength is not obtained with the conventional propylene-ethylene random copolymer containing the propylene-ethylene random copolymer. When the melting point of the propylene-ethylene random copolymer is increased, the adhesive strength is slightly improved, but the processability of the nonwoven fabric is lowered and the flexibility of the nonwoven fabric itself is impaired. As described above, the processability or flexibility of the nonwoven fabric and the adhesive strength are in a contradictory relationship, and the actual situation is that an ultrasonic fusion-molded article having good flexibility and good adhesion has not been obtained.
JP-A-62-156310 JP-A-10-298824

  In view of the present situation, the present invention has an object to provide a polypropylene-based nonwoven fabric molded article that eliminates the above-described drawbacks, is excellent in low-temperature processability during the production of nonwoven fabrics, and is superior in ultrasonic fusion properties in final product processing. To do.

  In order to solve the above-mentioned problems, the present inventors have intensively studied to obtain a nonwoven fabric excellent in low-temperature processability during production of a nonwoven fabric and excellent in ultrasonic fusion characteristics in final product processing. It has been found that a specific polymerized propylene / α-olefin random copolymer is suitable as a nonwoven fabric material having excellent low-temperature processability during the production of a nonwoven fabric and excellent ultrasonic fusing characteristics in the final processed product. It has come.

That is, according to the first invention of the present invention, a non-woven fabric comprising a fiber polymerized by a metallocene catalyst and having at least one component of a propylene / α-olefin random copolymer having the following characteristics (1) to (6): A polypropylene-based nonwoven fabric molded body obtained by ultrasonically fusing an adherend is provided.
Characteristic (1): MFR is 10 to 100 g / 10 minutes Characteristic (2): Q value is 2 to 4
Characteristic (3): Tm is 110 to 140 ° C.
Characteristic (4): The temperature (T ₁₀ ) when the soluble amount of o-dichlorobenzene is 10% by weight is 60 to 80 ° C.
Characteristic (5): α-olefin content (α) is 1 to 18 mol%
Characteristic (6): Tensile modulus (YM) and α-olefin content (α) satisfy formula (a) YM ≦ −52.3 × α + 1100 Formula (a)

In addition, according to the second invention of the present invention, there is provided a polypropylene-based nonwoven fabric molded body according to the first invention, wherein the propylene / α-olefin random copolymer further has the following property (7): Is done.
Characteristic (7): Tm and α-olefin content (α) satisfy formula (b) Tm ≦ −4.07 × α + 153.3 Formula (b)

  According to a third aspect of the present invention, there is provided a polypropylene-based nonwoven fabric molded body according to the first or second aspect, wherein the α-olefin of the propylene / α-olefin random copolymer is ethylene. Is done.

  According to the fourth aspect of the present invention, in any one of the first to third aspects, the fiber containing at least one component of the propylene / α-olefin random copolymer is a single fiber, a core-sheath type composite fiber Alternatively, there is provided a polypropylene-based nonwoven fabric molded body characterized by being a side-by-side composite fiber.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the nonwoven fabric made of fibers containing at least one component of a propylene / α-olefin random copolymer is a spunbond method, a melt blown method. Provided is a polypropylene-based nonwoven fabric molded article, which is a sheet-like nonwoven fabric produced by any one of the method, hydroentanglement method or card method.

According to a sixth invention of the present invention, in any one of the first to fifth inventions, in a nonwoven fabric having a basis weight of 40 g / m ² , the peel strength (PS) by ultrasonic fusion is 15 N / 15 mm width or more, And the polypropylene-type nonwoven fabric molded object characterized by peeling strength (PS) and nonwoven fabric elastic modulus (WM) satisfy | filling Formula (c) is provided.
WM ≦ 12.4 × PS + 50 Formula (c)

  Moreover, according to 7th invention of this invention, the sanitary material using the polypropylene-type nonwoven fabric molded object of the invention in any one of 1st-6th is provided.

  Moreover, according to the 8th invention of this invention, the paper diaper using the polypropylene-type nonwoven fabric molded body of the invention in any one of the 1st-6th is provided.

  According to the ninth aspect of the present invention, there is provided a mask using the polypropylene-based nonwoven fabric molded body according to any one of the first to sixth aspects.

  Moreover, according to the 10th invention of this invention, the tea bag using the polypropylene-type nonwoven fabric molded body of the invention in any one of the 1st-6th is provided.

  When a non-woven fabric comprising at least one component of the propylene / α-olefin random copolymer used in the present invention, a polypropylene-based non-woven fabric having excellent low-temperature processability during production of the non-woven fabric and excellent ultrasonic fusing characteristics; Therefore, the final processed product can be easily obtained by the ultrasonic fusion method.

  The present invention is a polypropylene-based nonwoven fabric molded body obtained by ultrasonically fusing a polypropylene-based nonwoven fabric composed of fibers containing a propylene / α-olefin random copolymer as at least one component and an adherend. Hereinafter, the present invention will be described in detail.

1. Propylene / α-olefin random copolymer The propylene / α-olefin random copolymer used in the polypropylene nonwoven fabric of the present invention is a copolymer of propylene and α-olefin polymerized using a metallocene catalyst. The metallocene catalyst is a catalyst using a complex of a group 4-6 transition metal such as titanium, zirconium, hafnium and the like and a group of a cyclopentadienyl group or a cyclopentadienyl derivative.

  In the metallocene catalyst, the group of the cyclopentadienyl derivative includes an alkyl substituent such as pentamethylcyclopentadienyl, or a group in which two or more substituents are combined to form a saturated or unsaturated cyclic substituent. Typically, an indenyl group, a fluorenyl group, an azulenyl group, or a partial hydrogenated product thereof can be used. Further, those in which a plurality of cyclopentadienyl groups are bonded by an alkylene group, a silylene group, a germylene group or the like are also preferably used.

Specific examples of the metallocene complex include the following compounds. (1) methylenebis (cyclopentadienyl) zirconium dichloride, (2) methylene (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) zirconium dichloride, (3) isopropylidene (cyclopentadienyl) (3 , 4-dimethylcyclopentadienyl) zirconium dichloride,
(4) ethylene (cyclopentadienyl) (3,5-dimethylpentadienyl) zirconium dichloride,
(5) methylenebis (indenyl) zirconium dichloride,
(6) ethylenebis (2-methylindenyl) zirconium dichloride,
(7) ethylene 1,2-bis (4-phenylindenyl) zirconium dichloride,
(8) ethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride,
(9) Dimethylsilylene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride,
(10) Dimethylsilylenebis (indenyl) zirconium dichloride

  In addition, compounds in which one or both of the chlorides of these compounds are replaced with bromine, iodine, hydrogen, methylphenyl, benzyl, alkoxy, dimethylamide, diethylamide and the like can also be exemplified. Furthermore, instead of the above-mentioned zirconium, compounds in place of titanium, hafnium and the like can be exemplified.

  The co-catalyst is selected from the group consisting of an ionic compound capable of reacting with an aluminum oxy compound, a metallocene compound to convert a metallocene compound component into a cation, or a Lewis acid, a solid acid, or an ion-exchange layered silicate. At least one compound selected is used. Moreover, an organoaluminum compound can be added with these compounds as needed.

  Examples of the aluminum oxy compound include methylalumoxane, ethylalumoxane, propylalumoxane, butylalumoxane, isobutylalumoxane, methylethylalumoxane, methylbutylalumoxane, methylisobutylalumoxane and the like.

  As the ion-exchange layered silicate, silicates of smectite group such as montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stevensite, bentonite, teniolite, vermiculite group, mica group and the like are used. These silicates are preferably those subjected to chemical treatment such as (i) acid treatment, (b) alkali treatment, (c) salt treatment, and (d) organic matter treatment.

  If necessary, organic aluminum compounds such as triethylaluminum, triisobutylaluminum, and diethylaluminum chloride may be used together with these compounds.

  In the present invention, a propylene / α-olefin random copolymer is obtained using the metallocene catalyst. Examples of the α-olefin include α-olefins having 2 to 20 carbon atoms excluding propylene, such as ethylene, butene-1, pentene-1, 3-methyl-1-butene, hexene-1, and 3-methyl-1. -Pentene, 4-methyl-1-pentene, heptene-1, octene-1, nonene-1, decene-1, dodecene-1, tetradecene-1, hexadecene-1, octadecene-1, eicosene-1, etc. . The α-olefin copolymerized with propylene may be used alone or in combination of two or more. Of these, ethylene and butene-1 are preferable, and ethylene is particularly preferable.

  Examples of the polymerization method include a slurry method using an inert solvent in the presence of these catalysts, a gas phase method or a solution method using substantially no solvent, or a bulk polymerization method using a polymerization monomer as a solvent.

  The propylene / α-olefin random copolymer used in the present invention is a copolymer polymerized by the metallocene catalyst described above, and has the following characteristics (1) to (6), preferably further characteristics (7) to It is necessary to have (9). The propylene / α-olefin copolymer having the characteristics (1) to (6) defined by the present invention, preferably the characteristics (7) to (9), is selected in addition to the selection of the comonomer type and the polymerization method. Furthermore, a desired polymer can be obtained by adjusting the polymerization temperature and the comonomer amount and appropriately controlling the molecular weight and the crystallinity distribution. Hereinafter, each characteristic will be described.

Characteristic (1): MFR
The melt flow rate (MFR) at 230 ° C. and 21.18 N according to the JIS-K6921-2 appendix of the propylene / α-olefin random copolymer used in the present invention is 10 to 100 g / 10 min, preferably 12 It is -90g / 10min, More preferably, it is 15-80g / 10min. When the MFR is less than 10 g / 10 minutes, the spinning pressure becomes too high, and it becomes difficult to stretch at a high magnification, resulting in problems such as uneven fiber diameter. On the other hand, if it exceeds 100 g / 10 min, the melt viscosity is low, so that the yarn sway becomes remarkable at the time of spinning, resulting in the disadvantage that adjacent yarns are fused together and yarn breakage occurs frequently. In order to adjust the MFR of the polymer, for example, there are a method of appropriately adjusting a polymerization temperature, a catalyst amount, a supply amount of hydrogen as a molecular weight regulator, or a method of adjusting by adding a peroxide after the polymerization is completed.

Characteristic (2): Q value The Q value of the propylene / α-olefin random copolymer used in the present invention is a ratio (Mw / Mn) of the weight average molecular weight Mw and the number average molecular weight Mn measured by GPC, It is 2-4, Preferably it is 2.2-3.7, More preferably, it is 2.3-3.5. When the Q value exceeds 4, there is a problem that the spin drawability is impaired due to the presence of the high molecular weight. On the other hand, if it is less than 2, the high molecular weight component is too small, the viscosity of the molten fiber immediately below the spinning nozzle becomes low, and the accompanying yarn wobbling becomes remarkable, and the spinning stability is impaired.
The method of adjusting the Q value of the propylene / α-olefin random copolymer is polymerized using a catalyst system in which two or more metallocene catalyst components are used in combination or a catalyst system in which two or more metallocene complexes are used in combination. Sometimes, the Q value can be widely controlled by carrying out multistage polymerization of two or more stages. Conversely, in order to narrowly adjust the Q value, it can be adjusted by polymerizing a propylene / α-olefin random copolymer and then melt-kneading it using an organic peroxide.

The specific measurement of the Q value was performed under the following conditions.
Apparatus: Waters HLC / GPC 150C
Column temperature: 135 ° C
Solvent: o-dichlorobenzene Flow rate: 1.0 ml / min
Column: manufactured by Tosoh Corporation GMH _HR- H (S) HT 60 cm × 1
Injection volume: 0.15 ml (no filtration treatment)
Solution concentration: 5 mg / 3.4 ml
Sample preparation: Use o-dichlorobenzene to prepare a 5 mg / 3.4 ml solution and dissolve at 140 ° C. for 1 to 3 hours.
Calibration curve: A polystyrene standard sample was used.
Calibration curve order: primary PP molecular weight: PS × 0.639

Characteristic (3): Tm
Tm of the propylene / α-olefin random copolymer used in the present invention represents a peak temperature of a melting curve obtained by a differential scanning calorimeter (DSC), and is 110 to 140 ° C, preferably 115 to 135 ° C. Preferably it is 120-130 degreeC. When Tm exceeds 140 ° C., it is not preferable from the viewpoint of energy cost during processing of the nonwoven fabric. Moreover, when it is less than 110 degreeC, when using with a tea bag etc., there exists a possibility of partial melting in boiling water, it is not preferable.
In order to adjust Tm, it can adjust easily by controlling the quantity of the alpha olefin supplied to a polymerization reaction system.

  The specific measurement of Tm was performed by using a differential scanning calorimeter (DSC) manufactured by Perkin Elmer, taking a sample amount of 10 mg, holding it at 200 ° C. for 5 minutes, and then decreasing the temperature to 40 ° C. at a rate of 10 ° C./min. The peak position of the curve drawn when crystallizing and further melting at a heating rate of 10 ° C./min was defined as the melting peak temperature Tm (° C.).

Characteristic (4): T ₁₀ (temperature when the amount of o-dichlorobenzene soluble component is 10% by weight)
The temperature (T ₁₀ ) when the o-dichlorobenzene soluble content of the propylene / α-olefin random copolymer used in the present invention is 10% by weight is 50 ° C. or higher, preferably 55 ° C. or higher, more preferably 60 It is above ℃. The upper limit of the T ₁₀ is not particularly defined, but, considering the balance between the melting point (Tm), it is about 80 ° C.. When T ₁₀ is less than 50 ° C., the low melting point component increases, which causes stickiness of the constituent fibers and surface stickiness when the nonwoven fabric is formed, and deteriorates the ultrasonic fusion characteristics. In addition, problems such as a decrease in spinning performance also occur. It T ₁₀ of polymer is 50 ° C. or higher, it means that the molecular weight distribution of the polymer is more homogeneous. This is caused by polymerization using a metallocene catalyst, and it is difficult to produce such a polymer with a Ziegler-Natta catalyst.
Method of adjusting the T ₁₀ of the propylene · alpha-olefin random copolymer by polymerization using a catalyst system in combination with the combination catalyst system and two or more metallocene complexes of two or more metallocene catalyst components, it is possible to increase the size T _10.
Further, upon supporting a metallocene catalyst component on a carrier, if the carrier is polymerized by using a catalyst which is heterogeneous, low molecular weight component increases, the T ₁₀ Accordingly increases. Therefore, a technique for uniformly supporting the metallocene catalyst component on the support is important.
Here will _be described later measurement of _{T 10.}

Characteristic (5): α-olefin content The α-olefin (comonomer) content in the propylene / α-olefin random copolymer used in the present invention is 1 to 18 mol%, preferably 2.5 to 10%. It is mol%, More preferably, it is 3-8 mol%. In particular, when the comonomer is ethylene, 1 to 12 mol% is preferable. When the comonomer content is less than the above range, the melting point is high, and the heat seal characteristics are not improved, which is not preferable. On the other hand, if the amount is too large, solidification during spinning is slow, productivity is impaired, and the strength and rigidity of the nonwoven fabric are greatly reduced. The α-olefin content in the polymer can be easily adjusted by controlling the amount of α-olefin supplied to the polymerization reaction system. In the present invention, the α-olefin content is determined by a Fourier transform infrared spectrophotometer.

Characteristic (6): Relationship between tensile modulus (YM) and α-olefin content The propylene / α-olefin random copolymer used in the present invention has an α-olefin content (α) and a tensile modulus (YM). The relationship must satisfy formula (a), preferably formula (a ′).
YM ≦ −52.3 × α + 1100 Formula (a)
YM ≦ −52.3 × α + 1050 Formula (a ′)
Formula (a) is a formula derived based on many experimental results, and shows that the amount of α-olefin in the copolymer effectively lowers the tensile modulus. When the formula (a) is not satisfied, α-olefin is present as a low-molecular sticky component, which is not preferable because the peel strength of the ultrasonic fused portion is reduced. The lower limit of YM is not particularly defined, but is about 500 MPa from the viewpoint of stable production at a manufacturing plant.
In the propylene / α-olefin random copolymer, the method for adjusting the formula (a) can be adjusted by controlling the feed amount of the α-olefin at the time of polymerization. It can be adjusted by removing.

Characteristic (7): Relationship between Tm and α-olefin content In the propylene / α-olefin random copolymer used in the present invention, the relationship between α-olefin content (α) and Tm is the formula (b), preferably ( It is preferable to satisfy b ′).
Tm ≦ −4.07 × α + 153.3 Formula (b)
Tm ≦ −4.07 × α + 150.3 Formula (b ′)
Formula (b) is a formula derived based on many experimental results, and shows that the amount of α-olefin in the copolymer effectively lowers the melting point. When the formula (b) is not satisfied, the α-olefin exists as a low-molecular sticky component, and thus there is a possibility that the peel strength of the ultrasonic fusion part is lowered.
In the propylene / α-olefin random copolymer, the method of adjusting the formula (b) can be adjusted by the same method as in the case of the formula (a).

Characteristic (8): T ₈₀ -T ₂₀ (elution amount difference temperature by TREF)
In the integral elution curve obtained by temperature rising elution fractionation (TREF), the propylene / α-olefin random copolymer used in the present invention has a temperature (T ₈₀ ) at which ₈₀ % by weight is eluted and 20% by weight. The difference in temperature (T ₂₀ ) at which elution occurs, T ₈₀ -T ₂₀ is preferably 10 ° C. or less, more preferably 2 to 9 ° C., and particularly preferably 2 to 8 ° C. When T ₈₀ -T ₂₀ exceeds 10 ° C., the low melting point component increases, which may cause stickiness of the constituent fibers and surface stickiness when made into a nonwoven fabric, and may deteriorate the ultrasonic fusion characteristics. Also, adverse effects such as a decrease in spinning performance are likely to occur. The T ₈₀ -T _{20 of the} polymer being in a specific narrow range as described above means that the molecular weight distribution of the polymer is more uniform. This is caused by polymerization using a metallocene catalyst, and it is difficult to produce such a polymer with a Ziegler-Natta catalyst.
The method for adjusting T ₈₀ -T ₂₀ of the propylene / α-olefin random copolymer is carried out by using a catalyst system in which two or more metallocene catalyst components are used in combination or a catalyst system in which two or more metallocene complexes are used in combination. it _makes it possible to increase the size T 80 _{-T 20.}
In addition, when a metallocene catalyst component is supported on a carrier and polymerized using a catalyst that is not uniformly supported, the low molecular weight component increases, and T ₈₀ -T ₂₀ increases accordingly. Therefore, a technique for uniformly supporting the metallocene catalyst component on the support is important.

  Here, the temperature rising elution fractionation (TREF) means that the polymer is completely dissolved at a constant high temperature in the presence of an inert carrier and then cooled to form a thin polymer layer on the surface of the inert carrier. In addition, the temperature is raised continuously or stepwise to recover the eluted component, its concentration is continuously detected, and the graph of the amount of elution and the elution temperature (integrated elution curve) shows the polymer This is a method for measuring the composition distribution. Details of the measurement of temperature rising elution fractionation (TREF) are described in Journal of Applied Polymer Science Vol. 26, pages 4217-4231 (1981), and are also carried out in the present invention.

T ₈₀ -T ₂₀ is specifically a value measured under the following conditions.
As a measuring apparatus, CFC T-102L manufactured by Dia Instruments was used.
First, a sample to be measured is dissolved at 140 ° C. using a solvent (o-dichlorobenzene) so as to be 3 mg / ml, and this is injected into a sample loop in the measuring apparatus. The following measurements are automatically performed according to the set conditions. The sample solution retained in the sample loop is separated into TREF columns (a stainless steel column attached to the apparatus with an inner diameter of 4 mm and a length of 150 mm filled with glass beads as an inert carrier) that is separated using the difference in dissolution temperature. 0.4 ml is injected. The sample is then cooled from 140 ° C. to 0 ° C. at a rate of 1 ° C./min. After the TREF column is held at 0 ° C. for another 30 minutes, 2 ml of components dissolved at the temperature of 0 ° C. are injected from the TREF column to the SEC column (three AD806MS manufactured by Showa Denko) at a flow rate of 1 ml / min. While molecular size fractionation is performed by SEC, the temperature is raised to the next elution temperature (10 ° C.) in the TREF column, and is maintained at that temperature for about 30 minutes. Measurement of each elution segment by SEC was performed at 39 minute intervals. The elution temperature is raised stepwise from 0 ° C to 40 ° C every 10 ° C, from 40 ° C to 90 ° C every 5 ° C, and from 90 ° C to 140 ° C every 4 ° C. The solution separated by the molecular size in the SEC column is detected by an infrared spectrophotometer attached to the apparatus, and a chromatograph in each elution temperature section is obtained. The detection by the infrared spectrophotometer is performed using the absorbance at a detection wave number of 3.42 μm, and the following data processing is performed assuming that the amount of polymer component in the solution is proportional to the absorbance. The chromatogram in each elution temperature section is processed by the built-in data processing software, and the elution amount of each elution temperature section normalized so that the integration is 100% is calculated based on the area of each chromatogram. Furthermore, an integrated elution curve is created from the elution amounts of the obtained elution temperature sections. The 0 ° C. soluble content indicates the amount (%) of the polymer component eluted at 0 ° C., T ₁₀ is the temperature at which the integrated elution amount is 10%, and T ₂₀ is the integrated elution amount is 20%. T ₈₀ indicates a temperature at which the integrated elution amount becomes 80%.

Characteristic (9): 0 ° C. soluble content at the time of TREF measurement The 0 ° C. soluble content at the time of TREF measurement of the propylene / α-olefin random copolymer used in the present invention is preferably 3% by weight or less, more preferably 2 0.8 wt% or less, particularly preferably 2.5 wt% or less. The low molecular weight component occupies most of the 0 ° C. soluble content at the time of TREF measurement, which causes the non-woven fabric to stick and deteriorates the ultrasonic fusion characteristics. If it is larger than the above range, the stickiness of the nonwoven fabric becomes noticeable, and as a result, the ultrasonic fusion properties deteriorate, which is not preferable.
The amount of TREF 0 ° C. soluble content of the propylene / α-olefin random copolymer increases when the metallocene catalyst component is supported on the carrier when polymerized using a catalyst that is non-uniformly supported. As a result, the amount of TREF 0 ° C. soluble component increases. Therefore, the amount of TREF 0 ° C. soluble component can be adjusted to 3% by weight or less by polymerization using a catalyst that uniformly supports the metallocene catalyst component on the carrier.

  In addition, the propylene / α-olefin random copolymer of the present invention includes various additives such as a heat stabilizer, an antioxidant, a weather stabilizer, an ultraviolet absorber, and the like within a range in which the object of the present invention is not impaired. Crystal nucleating agents, copper damage inhibitors, antistatic agents, slip agents, antiblocking agents, antifogging agents, colorants, fillers, elastomers, petroleum resins and the like can be blended.

  In the present invention, the propylene / α-olefin random copolymer and, if necessary, these various additives are melt-kneaded at 180 to 300 ° C. in a dry blend state or using a melt-kneader to form granules. It is provided as a fiber nonwoven fabric molding material in the state of a cut pellet.

2. Non-woven fabric The polypropylene-based non-woven fabric used in the present invention is produced by directly producing a fiber non-woven molding material using the above-mentioned propylene / α-olefin random copolymer as at least one component by a spunbond method, a melt-blown method, etc. It is manufactured by molding methods such as hydroentanglement method and card method. The basis weight of the nonwoven fabric is preferably 5 to 200 g / m ² . In addition, the nonwoven fabric is not only used as a single layer, but also suitable as, for example, a laminate of a nonwoven fabric obtained by a spunbond method and a nonwoven fabric obtained by a melt blown method, or a laminate of a nonwoven fabric and a film or water absorbent paper Can be used.
Here, the fiber having at least one component is a fiber composed of a composition of a propylene / α-olefin random copolymer and another resin component, or a propylene / α-olefin random copolymer and another resin component. It is also meant to include the composite fiber.

  When forming a nonwoven fabric, the fiber containing at least one component of propylene / α-olefin random copolymer may be a single fiber, a core-sheath type composite fiber, or a side-by-side type composite fiber. The fiber from the propylene / α-olefin random copolymer may be contained as one component of either fiber.

3. Nonwoven fabric molded body The nonwoven fabric molded body of the present invention is obtained by ultrasonically fusing the nonwoven fabric obtained above and the adherend. There are no particular restrictions on the material and shape of the adherend, but the materials include metals such as aluminum and their alloys, synthetic resins such as polypropylene and polystyrene, natural rubber, paper, glass, minerals, ceramics, natural fibers, etc. Examples of the shape include a foil shape, a cylindrical shape, a film shape, and a cloth shape. The non-woven fabric of the present invention may be an adherend. When the adherend is made of a different material, sufficient adhesive strength may not be obtained. Therefore, polypropylene is preferable, and the propylene / α-olefin copolymer used in the present invention is more preferable.
There is no restriction | limiting in particular in the method of ultrasonic fusion, It can carry out using a well-known ultrasonic fusion apparatus. In particular, an oscillation frequency of 25 to 35 kHz, a pressing force of 20 to 800 N, and a pressing time of 0.1 to 20 seconds are preferable because stable adhesive strength can be obtained.

Here, when the nonwoven fabric used in the present invention is used as the adherend, the nonwoven fabrics are ultrasonically fused (oscillation frequency: 28.7 kHz, pressurization: 200 N, pressurization time: 1 second). The peel strength (PS) of the nonwoven fabric is preferably 15 N / 15 mm width or more, more preferably 20 N / 15 mm when the basis weight of the nonwoven fabric is 40 g / m ² . When the peel strength is less than 15 N / 15 mm width, in the case of a paper diaper or the like, the joint is easily peeled off by an external force, which is not preferable.

Furthermore, it is preferable that the elastic modulus (WM) and peel strength (PS) of the nonwoven fabric satisfy the formula (c).
WM ≦ 12.4 × PS + 50 Formula (c)
Formula (c) is a formula derived on the basis of numerous experimental results. If the nonwoven fabric molding does not satisfy Formula (c), even if only the peel strength is high, the nonwoven fabric elastic modulus is too high. When processed into a material, a paper diaper, a mask tea bag, etc., it becomes a rough hand and becomes unpreferable as a product.
Here, the measurement method of the peel strength (PS) of a nonwoven fabric is a method in which a nonwoven fabric having a size of 15 mm × 100 mm is ultrasonically fused and then measured under the condition of a tensile speed of 10 mm / min.
The elastic modulus (WM) of the nonwoven fabric is a value measured according to JIS K7127.

  The polypropylene-based nonwoven fabric molded body of the present invention uses a nonwoven fabric that has excellent low-temperature processability during nonwoven fabric production and excellent ultrasonic fusing characteristics in final product processing, so sanitary materials such as paper diapers and sanitary napkins, It can be suitably used for medical materials such as masks and foods such as tea bags.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to the following Example, unless the summary is exceeded. The physical properties are measured as follows. Moreover, the manufacturing method of the propylene / alpha-olefin copolymer used by the Example and the comparative example was shown to the polymerization example.

1. Measurement method (1) MFR: Measured according to JIS-K6921-2 appendix. (Conditions: temperature 230 ° C., load 21.18 N)
(2) Ethylene content: measured with an infrared spectrophotometer.
(3) Q value: Measured according to the measurement method described above.
In addition, the polystyrene standard sample of Table 1 was used for the analytical curve.

(4) Melting peak temperature (Tm): Measured according to the measurement conditions described above using a differential scanning calorimeter (DSC) manufactured by PerkinElmer.
_{(5) T 10, T 80} -T 20 by temperature rising elution fractionation (TREF), 0 ° C. soluble content: measuring apparatus using a CFC T-102L manufactured by Dia Instruments, was measured according to the measurement conditions described above.
(6) Resin tensile modulus (YM): Measured according to JIS K7113.
(7) Nonwoven fabric elastic modulus (WM): Using a Toyo Seiki strograph, a test piece of 10 cm in length and 5 cm in width was measured under the conditions of a tensile speed of 1 mm / min, a chuck interval of 50 mm, and a chart speed of 50 mm / min. Obtained from the equation.
Nonwoven fabric elastic modulus [MPa] = 1% elongation load / nonwoven fabric cross-sectional area / elongation rate (0.01)
(Here, the non-woven fabric cross-sectional area was defined as test piece weight / density (0.9 g / cm ³ ) / test piece area (50 cm ² ).)
(8) Peel strength (PS): Using Tensilon manufactured by Toyo Seiki, peeling at 180 degrees, and the load per sample unit width when peeling at a tensile rate of 10 mm / min was defined as peel strength (unit: N / 15 mm) ).

2. Production Method of Propylene / α-Olefin Copolymer Polymers I to VII obtained in the following Polymerization Examples 1 to 7 were used as the propylene / α-olefin copolymer used in Examples and Comparative Examples. Table 2 shows the physical properties of the polymer. Polymers I to IV are propylene / ethylene random copolymers of the present invention having characteristics (1) to (9), and polymers V to VII are copolymers outside the present invention.

(Polymerization example 1)
(1) Preparation of catalyst 20 g of smectite group silicate (Benley SL manufactured by Mizusawa Chemical Co., Ltd.), which was sequentially treated with sulfuric acid, in a three-necked flask (volume: 1 L) and 200 mL of heptane were charged with 50 mmol of trinormal octylaluminum After contact, the slurry was washed with heptane to obtain slurry 1. In another flask (volume 200 mL), heptane 90 mL, [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium] 0 .3 mmol and triisobutylaluminum 1.5 mmol were charged to make slurry 2. Slurry 2 was added to the slurry 1 and stirred at room temperature for 60 minutes. Thereafter, 210 mL of heptane was added, and this slurry was introduced into a 1 L autoclave. After the internal temperature of the autoclave was set to 40 ° C., propylene was fed at a rate of 10 g / hour, and prepolymerization was carried out for 4 hours while maintaining 40 ° C. to obtain 83 g of a prepolymerized catalyst.
(2) Production of propylene / α-olefin random copolymer A hexane-diluted solution of liquid propylene, ethylene, hydrogen, and triisobutylaluminum (TIBA) was continuously supplied to a reactor having an internal volume of 270 L, and the internal temperature was 62. Held at 0C. The supply amount of propylene was 38 kg / hr, the supply amount of ethylene was 1.1 kg / hr, the supply amount of hydrogen was 0.24 g / hr, and the supply amount of TIBA was 18 g / hr. The prepolymerized catalyst was slurried with liquid paraffin and fed at 1.2 g / hr. As a result, 14.5 kg / hr of a propylene / ethylene random copolymer (polymer I) was obtained. The obtained propylene / ethylene random copolymer I had MFR = 22 g / 10 min, ethylene content = 5.0 mol%, Tm = 12.5 ° C., and Q value = 2.7.

(Polymerization example 2)
Polymerization Example 1 except that the solid catalyst prepared in Polymerization Example 1 was used, the hydrogen supply amount was changed to 0.36 g / hr, and the feed amount in which the prepolymerization catalyst was slurried with liquid paraffin was changed to 0.87 g / hr. Polymerization was carried out in the same manner as described above. As a result, 11.6 kg / hr of a propylene / ethylene random copolymer (Polymer II) was obtained. Polymer II had MFR = 39 g / 10 min, ethylene content = 5.0 mol%, Tm = 12.5 ° C., and Q value = 2.8.

(Polymerization example 3)
Using the solid catalyst prepared in Polymerization Example 1, the amount of ethylene supplied was 0.85 kg / hr, the amount of hydrogen supplied was 0.42 g / hr, and the prepolymerized catalyst was slurried with liquid paraffin to a feed amount of 1.95 g. Polymerization was carried out in the same manner as in Polymerization Example 1 except that it was changed to / hr. As a result, 12.0 kg / hr of a propylene / ethylene random copolymer (Polymer III) was obtained. The obtained polymer III had MFR = 40 g / 10 min, ethylene content = 4.1 mol%, Tm = 130.1 ° C., and Q value = 2.7.

(Polymerization example 4)
Polymerization was carried out in the same manner as in Polymerization Example 1 except that the solid catalyst prepared in Polymerization Example 1 was used and the ethylene supply rate was changed to 1.6 kg / hr. As a result, 12.5 kg / hr of a propylene / ethylene random copolymer (Polymer IV) was obtained. The obtained polymer IV had MFR = 22 g / 10 min, ethylene content = 6.0 mol%, Tm = 120.2 ° C., and Q value = 2.8.

(Polymerization Example 5)
Polymerization Example 1 except that the solid catalyst prepared in Polymerization Example 1 was used, the hydrogen supply amount was changed to 0.03 g / hr, and the feed amount in which the prepolymerization catalyst was slurried with liquid paraffin was changed to 1.5 g / hr. Polymerization was carried out in the same manner as described above. As a result, a 12.5 kg / hr propylene / ethylene random copolymer (polymer V) was obtained. The obtained polymer V had MFR = 6 g / 10 min, ethylene content 5.0 mol%, Tm = 12.5 ° C., and Q value = 2.7.

(Polymerization Example 6)
After fully replacing the stirred autoclave with an internal volume of 200 liters with propylene, 60 L of dehydrated and deoxygenated n-heptane was introduced, 16 g of diethylaluminum chloride, titanium trichloride catalyst (manufactured by M & M Co.) 4 0.1 g was introduced at 50 ° C. in a propylene atmosphere. Further, while maintaining the gas phase hydrogen concentration at 6.0 vol.%, Propylene was fed at a rate of 5.7 kg / hr and ethylene at a rate of 0.28 kg / hr for 4 hours at a temperature of 50 ° C., and then the polymerization was continued for another hour. . As a result, 12 kg of propylene / ethylene random copolymer (polymer VI) was obtained. The obtained polymer VI had MFR = 6.4 g / 10 min, ethylene content = 5.9 mol%, Tm = 140.0 ° C., and Q value = 4.4.

(Polymerization Example 7)
Polymerization was conducted in the same manner as in Polymerization Example 6 except that the amount of ethylene supplied was 0.35 kg / hr. As a result, 11 kg of propylene / ethylene random copolymer VII (polymer VII) was obtained. The obtained polymer VII had MFR = 6 g / 10 min, ethylene content = 6.5 mol%, Tm = 130.0 ° C., and Q value = 4.5.

(Examples 1-4)
1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl]-as an antioxidant with respect to 100 parts by weight of the powders of polymers I to IV shown in Table 2 0.04 parts by weight of 1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (product name, Cyanox 1790, manufactured by Cytec), tris- (2,4-di-t- (Butylphenyl) phosphite (Ciba Specialty Chemicals, trade name: Irgafos 168) and 0.05 parts by weight of calcium stearate (Nitto Kasei Kogyo, trade name: Ca-St) as a neutralizing agent After mixing and mixing at 500 rpm for 3 minutes with a Henschel mixer, using a φ50 mm single screw extruder (manufactured by Union Plastics), melting at an extrusion temperature of 230 ° C. Kneading, cooling, to prepare a pellet-like propylene copolymer composition was cut.
Next, the obtained composition was melt-spun using a single spinneret having 24 holes. The melt spinning was performed at a spinning temperature of 230 ° C., a discharge rate of 0.8 g / min / hole, and then drawn by air soccer to obtain a single fiber having a fineness of 2 denier. After the fibers were accumulated on a conveyor under the air soccer, the fibers were fused together by an embossing roll set at a predetermined temperature to obtain a nonwoven fabric having a basis weight of 40 g / m ² .
In addition, embossing roll temperature was made into Example 1-2: 114 degreeC, Example 3: 119 degreeC, and Example 4: 109 degreeC.
The obtained non-woven fabric 15 mm wide × 100 mm long test pieces were superposed, and using a SONEPET ΣG-620 manufactured by Seidensha Electronics Co., Ltd., oscillation frequency: 28.7 kHz, pressure: 200 N, pressure time: 1 second, ultrasonic wave After fusing, the peel strength was measured. The results are shown in Table 3.

(Example 5)
The propylene / ethylene random copolymer (polymer I) composition prepared in Example 1 is used as the first component (sheath material) raw material, and the second component (core material) raw material is homopolypropylene (SA04C: Nippon Polypro). The core-sheath ratio was 1/1 (weight ratio), and melt spinning was performed using a core-sheath type spinneret with 24 holes.
The melt spinning was performed at a spinning temperature of 230 ° C. and a discharge rate of 0.8 / min / hole, and then drawn by air soccer to obtain a core-sheath type composite fiber having a fineness of 2 denier. After this composite fiber was accumulated on the conveyor under the air soccer, the fibers were fused together by an embossing roll set at 114 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² . The obtained nonwoven fabric was subjected to ultrasonic fusion, and the peel strength was measured. The results are shown in Table 3.

(Example 6)
A nonwoven fabric having a basis weight of 40 g / m ² was obtained in the same manner as in Example 5 except that the second component (core material) was metallocene polyethylene (KS560: manufactured by Nippon Polyethylene) and the embossing roll temperature was 109 ° C. The obtained nonwoven fabric was subjected to ultrasonic fusion, and the peel strength was measured. The results are shown in Table 3.

(Comparative Example 1)
A nonwoven fabric having a basis weight of 40 g / m ² was obtained in the same manner as in Example 1 except that homopolypropylene (SA04C: manufactured by Nippon Polypro Co., Ltd.) was used and the embossing roll temperature was 145 ° C. The obtained nonwoven fabric was subjected to ultrasonic fusion, and the peel strength was measured. The results are shown in Table 3.

(Comparative Examples 2-3)
0.03 parts by weight of a peroxide (Perhexa 25B: manufactured by NOF Corporation) was added to the polymers VI and VII, and a polymer prepared so that the final MFR was 25 g / 10 min was used as a sheath material. A nonwoven fabric was obtained in the same manner as in Example 5. However, in Comparative Example 2, the embossing roll temperature was 131 ° C., and in Comparative Example 3, 120 ° C. The obtained nonwoven fabric was subjected to ultrasonic fusion, and the peel strength was measured. The results are shown in Table 3.

(Comparative Example 4)
In Example 5, the first component (sheath material) is high density polyethylene (HE490: manufactured by Nippon Polyethylene Co., Ltd.), the second component (core material) is homopolypropylene (SA04C: manufactured by Nippon Polypro Co., Ltd.), and the embossing roll temperature is 130. A non-woven fabric having a basis weight of 40 g / m ² was obtained in the same manner except that the temperature was changed to ° C. The obtained nonwoven fabric was subjected to ultrasonic fusion, and the peel strength was measured. The results are shown in Table 3.

(Comparative Example 5)
Using the polymer V powder, the polymer V composition prepared in the same manner as in Example 1 is used as the first component (sheath material) raw material, and the second component (core material) raw material is homopolypropylene (SA04C: Japan). Polypropylene Co., Ltd.) was used, and melt spinning was performed using a core-sheath type spinneret. However, the stretchability in air soccer was very poor, and many stretch breaks occurred, so a nonwoven fabric could not be obtained. It was.

(Comparative Example 6)
A polymer V was prepared in the same manner as in Example 1 except that 0.05 part by weight of a peroxide (Perhexa 25B: manufactured by NOF Corporation) was added, MFR = 60 g / 10 min, Q value = 1.8. Of polymer V ^* was obtained. The composition is used as the first component (sheath material), homopolypropylene (SA04C: manufactured by Nippon Polypro Co., Ltd.) is used as the second component (core material), and melt spinning using a core-sheath type spinneret. However, the fusion due to the yarn shaking of the molten fiber directly under the spinneret occurred remarkably, and a nonwoven fabric could not be obtained.

  As is clear from Table 3, according to each of the examples shown above, a polypropylene-based nonwoven fabric having high peel strength of the nonwoven fabric by ultrasonic fusion can be obtained. On the other hand, the nonwoven fabric of each comparative example has a high embossing roll temperature, a low peel strength by ultrasonic fusion, and does not exhibit the effects of the present invention.

  Since the polypropylene-based nonwoven fabric molded body of the present invention uses a nonwoven fabric from a specific propylene / α-olefin random copolymer, it is excellent in low-temperature processability during the production of the nonwoven fabric and has an ultrasonic fusion property in the final product processing. It can be suitably used for sanitary materials such as paper diapers and sanitary napkins, medical materials such as masks, and foods such as tea bags.

Claims (10)

Polypropylene obtained by ultrasonically fusing a non-woven fabric composed of fibers polymerized by a metallocene catalyst and having at least one component of a propylene / α-olefin random copolymer having the following characteristics (1) to (6) and an adherend: -Based nonwoven fabric molding.
Characteristic (1): MFR is 10 to 100 g / 10 minutes Characteristic (2): Q value is 2 to 4
Characteristic (3): Tm is 110 to 140 ° C.
Characteristic (4): The temperature (T ₁₀ ) when the soluble amount of o-dichlorobenzene is 10% by weight is 60 to 80 ° C.
Characteristic (5): α-olefin content (α) is 1 to 18 mol%
Characteristic (6): Tensile modulus (YM) and α-olefin content (α) satisfy formula (a) YM ≦ −52.3 × α + 1100 Formula (a) The polypropylene-based nonwoven fabric molded article according to claim 1, wherein the propylene / α-olefin random copolymer further has the following property (7).
Characteristic (7): Tm and α-olefin content (α) satisfy formula (b) Tm ≦ −4.07 × α + 153.3 Formula (b) The polypropylene-based nonwoven fabric molded article according to claim 1 or 2, wherein the α-olefin of the propylene / α-olefin random copolymer is ethylene.   The fiber comprising at least one component of propylene / α-olefin random copolymer is a single fiber, a core-sheath composite fiber, or a side-by-side composite fiber, according to any one of claims 1 to 3. The polypropylene-based nonwoven fabric molding described.   The non-woven fabric composed of fibers comprising at least one component of propylene / α-olefin random copolymer is a sheet-like non-woven fabric produced by any of the spun bond method, melt blow method, hydroentanglement method or card method. The polypropylene-based nonwoven fabric molded body according to any one of claims 1 to 4. In a nonwoven fabric with a basis weight of 40 g / m ^2, the peel strength (PS) by ultrasonic fusion is 15 N / 15 mm width or more, and the peel strength (PS) and the nonwoven fabric elastic modulus (WM) satisfy the formula (c). The polypropylene-based nonwoven fabric molded body according to any one of claims 1 to 5.
WM ≦ 12.4 × PS + 50 Formula (c)   A sanitary material using the polypropylene-based nonwoven fabric molded body according to any one of claims 1 to 6.   A paper diaper using the polypropylene-based nonwoven fabric molded body according to any one of claims 1 to 6.   The mask using the polypropylene-type nonwoven fabric molding of any one of Claims 1-6.   The tea bag using the polypropylene type nonwoven fabric molding of any one of Claims 1-6.