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WO1999043740A1 - Feuilles ayant une resistance a la rayure accrue - Google Patents

Feuilles ayant une resistance a la rayure accrue Download PDF

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Publication number
WO1999043740A1
WO1999043740A1 PCT/US1999/002067 US9902067W WO9943740A1 WO 1999043740 A1 WO1999043740 A1 WO 1999043740A1 US 9902067 W US9902067 W US 9902067W WO 9943740 A1 WO9943740 A1 WO 9943740A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
films
present
nylon
styrene
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1999/002067
Other languages
English (en)
Inventor
Wenbin Liang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Chemical Co
Original Assignee
Dow Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dow Chemical Co filed Critical Dow Chemical Co
Priority to AU24879/99A priority Critical patent/AU2487999A/en
Publication of WO1999043740A1 publication Critical patent/WO1999043740A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D27/00—Envelopes or like essentially-rectangular flexible containers for postal or other purposes having no structural provision for thickness of contents
    • B65D27/04—Envelopes or like essentially-rectangular flexible containers for postal or other purposes having no structural provision for thickness of contents with apertures or windows for viewing contents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
    • C08J2325/02—Homopolymers or copolymers of hydrocarbons
    • C08J2325/04—Homopolymers or copolymers of styrene
    • C08J2325/06—Polystyrene

Definitions

  • This invention relates to films having improved scratch resistance.
  • the present invention discloses how to make substantially clear films consisting predominately of polystyrene that are more resistant to scratches and abrasions than films of the prior art.
  • One particularly useful application of thin, substantially clear films is as window envelope film.
  • a window envelope is an envelope with one or more openings of any shape, usually rectangular, which allows examination of any information, typically a name and an address, printed on a limited area of matter within.
  • the opening or openings are sealed or closed by a window patch composed of a substantially clear film. Patching is the process in which window envelope film is cut into patches of a desired length and width, gummed around the edges, and applied to the window envelope. Alternatively, the edges of the window opening or openings may be gummed instead of the edges of the window patch.
  • the patching process requires the use of a vacuum drum to ensure proper positioning of the film. As the film passes over the surface of the vacuum drum there exists a disparity in the speed of the passing film and the angular velocity of the drum. This disparity of speed results in the abrasion and scratching of the film. If the abrasion and scratching is severe enough, particles are removed or flecked from the film surface resulting in film dust.
  • Prior art methods for substantially reducing or eliminating film dusting incorporate a waxy agent or an anti-flecking agent into window envelope films comprised predominately of polystyrene; see, for example, US-A- 4,961 ,800; US-A- 5,009,953; and US- A- 5,190,814.
  • films of the present invention when subjected to scratch testing, exhibit scratch resistance in two ways. First, upon visual inspection, films of the present invention have significantly fewer visible scratches than films of the prior art. Second, when films of the present invention are subjected to scratch testing, their haze value does not increase near as much as films of the prior art that are subjected to the same scratch testing.
  • films of the present invention comprise predominately polystyrene. Along with the polystyrene, films of the present invention also contain a styrenic block copolymer, a nylon copolymer, and optionally inorganic particulates. More particularly, the present invention concerns a substantially clear film which comprises polystyrene and from 0.1 to 10 weight percent of styrene block copolymer and from 0.1 to 4 weight percent of nylon copolymer. The present invention further concerns window envelopes having substantially clear window patches made from such films.
  • Films of the present invention are generally monolayer films and unless expressly stated otherwise the term "film” or “films” in the present specification will refer to monolayer films. However, it is within the scope of the present invention to produce a multilayer film comprising at least one scratch-resistant surface layer, wherein the scratch- resistant surface layer has the same composition as monolayer films of the present invention.
  • Films of the present invention are substantially clear. By substantially clear it is meant that the films are sufficiently clear so that, when films of the present invention are utilized as window envelope films to make window envelope patches, printed information, such as a name and address, can be readily examined through the film.
  • films of the present invention useful as window envelope film are at least 0.5 mils (12.7 micrometers ( ⁇ m)) thick, and preferably at least 0.9 mils (22.9 ⁇ m) thick. Films of the present invention useful as window envelope films are no more than 2 mils (50.8 ⁇ m) thick, and preferably no more than 1.4 mils (152.4 ⁇ m) thick. However, films of the present invention useful in other applications may be significantly thicker. For example, films of the present invention useful in certain lamination applications are up to 6 mils (152.4 ⁇ m) thick.
  • Films of the present invention are comprised predominately of polystyrene.
  • films of the present invention also contain a styrenic block copolymer, a nylon copolymer, and optionally inorganic particulates.
  • Films of the present invention may also contain small amounts of other additives, such as stabilizers or hazing agents.
  • stabilizers or hazing agents such as stabilizers or hazing agents.
  • 0.3 percent of stabilizer and 7 percent of high impact polystyrene is included.
  • films of the present invention contain at least 90 percent polystyrene, and preferably at least 95 percent polystyrene.
  • the type of polystyrene useful in the present invention is typically general purpose polystyrene ("GPPS").
  • the styrenic block copolymer effects the scratch-related surface failure of the polystyrene film when being scratched.
  • the styrenic block copolymer substantially reduces the brittle fracture and yields partial ductile fracture during scratching.
  • the addition of a styrenic block copolymer adds a rubbery component to the otherwise more brittle polystyrene surface. This rubbery component helps diminish the tendency for scratches to propagate in either the same direction or propagate away from the initial scratch in a direction approximately perpendicular to the initial scratch.
  • Preferred styrenic block copolymers include styrene-isoprene-styrene block copolymers ("SIS"), styrene-butadiene-styrene block copolymers (“SBS”), styrene-ethylene- propylene block copolymers (“SEP”), and hydrogenated styrenic block copolymer such as styrene-(ethylene butylene)-styrene block copolymers (“SEBS”) (e.g., KratonTM G1657).
  • SEBS styrene-(ethylene butylene)-styrene block copolymers
  • films of the present invention utilize SEBS.
  • films of the present invention have a sufficient amount of styrenic block copolymer present to produce the desired effects listed above. If too much styrenic block copolymer is present then the film becomes rubbery and difficult to cut.
  • films of the present invention comprise at least 0.1 percent styrenic block copolymer, preferably at least 0.3 percent styrenic block copolymer, and more preferably at least 0.4 percent styrenic block copolymer.
  • films of the present invention comprise no more than 10 percent styrenic block copolymer, preferably no more than 2 percent styrenic block copolymer, and more preferably no more than 1.4 percent styrenic block copolymer.
  • Films of the present invention also contain a nylon copolymer.
  • Nylon copolymers useful in the present invention will have a substantial amorphous fraction and have a melt temperature less than the temperature at which the film will be extruded.
  • nylon copolymers useful in the present invention have a melt temperature less than 200°C, and preferably a melt temperature less than 150°C. It is believed that the amorphous fraction of the nylon copolymer reduces flecking of scratched portions of the polystyrene matrix.
  • Nylon copolymers having lower melt temperatures disperse more readily at normal polystyrene melt-extrusion process temperatures than nylon copolymers having higher melt temperatures.
  • nylon particles have higher abrasion and scratch resistance than the general purpose polystyrene in the film. It is further believed that a more uniform dispersion of nylon copolymer in the polystyrene matrix promotes scratch resistance of the film.
  • Nylon copolymers useful in the present invention include nylon 6/6,9 copolymer (e.g., GrilonTM CF62SE) and nylon 6/12 copolymer (e.g., GrilonTM CA6E).
  • films of the present invention utilize nylon 6/6,9 copolymers.
  • films of the present invention contain a sufficient amount of nylon to produce the desired benefits of scratch resistance. If too much nylon is added, the film will not have the desired degree of transparency. Films of the present invention contain at least 0.1 percent of a nylon copolymer, and preferably at least 0.5 percent of a nylon copolymer. Films of the present invention contain no more than 4 percent of a nylon copolymer, and preferably no more than 2 percent of a nylon copolymer.
  • Films of the present invention also may optionally contain inorganic particulates.
  • the addition of very small amounts of inorganic particulates further improves the scratch resistance of the films of the present invention while at the same time dramatically reducing the amount of nylon necessary to promote scratch resistance in films of the present invention.
  • Inorganic particulates useful in the present invention will have a Mohs' hardness of 3 or higher, and preferably 6 or higher. Generally, particulates smaller in size are more useful in the present invention than particulates that are larger in size. It is believed that the smaller particle size helps reduce the tendency for scratches to propagate. Generally, inorganic particulates useful in the present invention will have an average particle size of no more than 5 ⁇ m, preferably no more than 2 ⁇ m, and more preferably no more than 1 ⁇ m.
  • Films of the present invention that utilize inorganic particulates will contain at least 0.005 percent of inorganic particulates, and preferably at least 0.01 percent. Films of the present invention contain less than 1 percent of inorganic particulates, preferably less than 0.2 percent, and more preferably less than 0.1 percent.
  • Inorganic particulates useful in the present invention include calcium carbonate, titanium dioxide ("Ti ⁇ 2")> and silicon dioxide ("Si ⁇ 2").
  • Ti ⁇ 2 titanium dioxide
  • Si ⁇ 2 silicon dioxide
  • inorganic particulates used in the present invention are Ti ⁇ 2 or Si ⁇ 2- More preferably, films of the present invention will utilize Ti ⁇ 2 as an inorganic particulate.
  • Ti ⁇ 2 is able to produce these scratch resistance benefits in substantially clear films because Ti ⁇ 2 is often used in the art as a pigment to color films.
  • the amount of Ti ⁇ 2 added can be sufficiently small so as to not give color to the film and noticeably affect the transparency of the film. Nonetheless, this small amount of Ti ⁇ 2 provides for significant scratch resistance benefits.
  • Films of the present invention may also include small amounts of other additives such as a stabilizer (e.g., IrganoxTM Bl 171).
  • a stabilizer e.g., IrganoxTM Bl 171.
  • some preferred embodiments of the present invention contain 0.05 to 0.3 percent of IrganoxTM Bl 171.
  • Films of the present invention may also contain a hazing agent.
  • Hazing agents useful in the present invention are taught, for example, in US-A- 5,190,814 at column 3, line 58 to column 4, line 42.
  • Films of the present invention can be made by conventional film producing techniques and processes known in the art, such as cast tentering and blown film processes.
  • the following examples illustrate the present invention further. As stated previously, unless otherwise indicated, all composition percentages are based upon weight. Examples
  • Film #1 was comprised of 0.6 percent of a SEBS block copolymer (KratonTM G1657X, available from Shell Chemical Company), 1.7 percent of a nylon 6/6,9 copolymer (GrilonTM CF62SE, available from EMS-American Grilon, Inc.), 0.03 percent Ti ⁇ 2, and 0.02 percent of high impact polystyrene ("HIPS").
  • the remaining composition of Film #1 was GPPS.
  • Film #2 had the same composition except that the nylon composition was 0.9 percent and the Ti ⁇ 2 composition was 0.04 percent.
  • a comparative film example representing the prior art was also produced.
  • This comparative example contained 99.8 percent GPPS and 0.2 percent polytetrafluoroethylene ("PTFE") and was produced according to the teachings of US-A- 5, 190,814.
  • the comparative example and Film #2 were tested for scratch resistance in the same manner as the two films discussed above except the bronze drum was under a vacuum of 12-in Hg (40.6 pKa) instead of 10-in Hg (33.9 pKa).
  • the comparative example exhibited a change in measured haze value of 84 percent and Film #2 exhibited a change in measured haze value of 2.4 percent.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

Des feuilles à base de polystyrène sensiblement transparentes contiennent principalement du polystyrène ainsi qu'un copolymère bloc styrénique, un copolymère de nylon et éventuellement des matières particulaires inorganiques. Lesdites feuilles présentent une résistance à la rayure accrue et sont particulièrement utiles en tant que feuilles d'enveloppe de fenêtres.
PCT/US1999/002067 1998-02-27 1999-01-29 Feuilles ayant une resistance a la rayure accrue Ceased WO1999043740A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU24879/99A AU2487999A (en) 1998-02-27 1999-01-29 Films having improved scratch resistance

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US7632498P 1998-02-27 1998-02-27
US60/076,324 1998-02-27

Publications (1)

Publication Number Publication Date
WO1999043740A1 true WO1999043740A1 (fr) 1999-09-02

Family

ID=22131289

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/002067 Ceased WO1999043740A1 (fr) 1998-02-27 1999-01-29 Feuilles ayant une resistance a la rayure accrue

Country Status (2)

Country Link
AU (1) AU2487999A (fr)
WO (1) WO1999043740A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002062876A3 (fr) * 2001-02-02 2003-06-12 Dow Global Technologies Inc Films a faible brillant et a orientation biaxiale contenant des polymeres aromatiques vinyle et des particules de caoutchouc sensiblement non spheriques
US8187685B2 (en) 2006-08-24 2012-05-29 Dow Chemical Technologies LLC Window envelopes with scratch resistant window film patches

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5009953A (en) * 1988-07-18 1991-04-23 The Dow Chemical Company Non-dusting window envelope film utilizing a particulate anti-flecking agent

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5009953A (en) * 1988-07-18 1991-04-23 The Dow Chemical Company Non-dusting window envelope film utilizing a particulate anti-flecking agent

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002062876A3 (fr) * 2001-02-02 2003-06-12 Dow Global Technologies Inc Films a faible brillant et a orientation biaxiale contenant des polymeres aromatiques vinyle et des particules de caoutchouc sensiblement non spheriques
US6579946B2 (en) 2001-02-02 2003-06-17 Dow Global Technologies Inc. Low-gloss biaxially oriented films comprising vinyl aromatic polymers and substantially non-spherical rubber particles
US8187685B2 (en) 2006-08-24 2012-05-29 Dow Chemical Technologies LLC Window envelopes with scratch resistant window film patches

Also Published As

Publication number Publication date
AU2487999A (en) 1999-09-15

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