1、BRITISH STANDARDBS EN 14932:2006Plastics Stretch thermoplastic films for wrapping bales Requirements and test methodsThe European Standard EN 14932:2006 has the status of a British StandardICS 55.040; 83.140.10g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g
2、50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14932:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2007 BSI 2007ISBN 978-0-580-49966-1National forewordThis
3、British Standard was published by BSI. It is the UK implementation of EN 14932:2006.The UK participation in its preparation was entrusted to Technical Committee PRI/75, Plastics and rubber film and sheets.A list of organizations represented on PRI/75 can be obtained on request to its secretary.This
4、publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EURO
5、PENNEEUROPISCHE NORMEN 14932December 2006ICS 55.040; 83.140.10English VersionPlastics - Stretch thermoplastic films for wrapping bales -Requirements and test methodsPlastiques - Films thermoplastiques tirables pour lenrubannage de balles - Exigences et mthodes dessaiKunststoffe - Thermoplastische St
6、retchfolien zumUmwickeln von Ballen - Anforderungen und PrfverfahrenThis European Standard was approved by CEN on 9 November 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standar
7、d without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other langua
8、ge made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,German
9、y, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManage
10、ment Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14932:2006: EEN 14932:2006 (E) 2 Contents Page 1 Scope .6 2 Normative references .6 3 Terms and definitions 7 4 Materials 7 5 Solar
11、 reflectance.8 6 Durability .8 7 Airtightness and oxygen permeability on bale8 8 Requirements9 8.1 General requirements.9 8.2 Requirement for appearance .10 9 Test methods.10 9.1 Determination of thickness10 9.2 Determination of width.10 9.3 Determination of core protrusion10 9.4 Determination of le
12、ngth of film10 9.5 Determination of neck-in11 9.6 Determination of tensile characteristics 11 9.7 Determination of impact resistance11 9.8 Determination of slow perforation characteristics11 9.9 Determination of the tightening force of films.12 9.10 Determination of tear resistance characteristics 1
13、2 9.11 Determination of adhesion 12 9.12 Determination of total light transmission 12 9.13 Determination of resistance to artificial weathering.12 9.13.1 Principle.12 9.13.2 Apparatus 12 9.13.3 Test conditions .12 9.13.4 Sampling13 9.13.5 Test procedure13 9.13.6 Results .13 9.14 Determination of oxy
14、gen permeability .13 10 Determination of leaktightness on the bale .13 11 Designation .13 12 Marking 14 EN 14932:2006 (E) 3 Annex A (normative) Determination of solar reflectance 15 A.1 Introduction.15 A.2 Principle.16 A.3 Terms and definitions 16 A.4 Determination of solar reflectance, Rs.17 A.4.1
15、Reflectance spectra acquisition .17 A.4.2 Calculation of Rs 17 Annex B (normative) Determination of neck-in characteristic19 B.1 Introduction.19 B.2 Apparatus19 B.3 Procedure20 Annex C (normative) Determination of perforation resistance.21 C.1 Principle.21 C.2 Description21 C.3 Apparatus21 C.4 Proce
16、dure21 C.4.1 Definitions .21 C.4.2 Conditioning .21 C.4.3 Specimen preparation21 C.4.4 Test conditions .22 C.4.5 Test procedure22 C.4.6 Number of tests 22 C.5 Results.22 Annex D (normative) Determination of tightening force25 D.1 Principle.25 D.2 Apparatus25 D.3 Procedure25 D.4 Preparation of the sp
17、ecimens .25 D.5 Results.26 D.6 Repeatability .26 Annex E (normative) Determination of adhesion characteristic.27 E.1 Principle.27 E.2 Apparatus27 E.3 Preparation of apparatus.27 E.4 Procedure32 Annex F (informative) Determination of leaktightness on the bale 33 F.1 Airtightness on an artificial bale
18、.33 F.2 Oxygen permeability on an artificial bale 33 EN 14932:2006 (E) 4 Foreword This document (EN 14932:2006) has been prepared by Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by IBN/BIN. This European Standard shall be given the status of a national standard, either
19、 by publication of an identical text or by endorsement, at the latest by June 2007, and conflicting national standards shall be withdrawn at the latest by June 2007. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implem
20、ent this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United
21、Kingdom. EN 14932:2006 (E) 5 Introduction The biological and practical requirements for silage stretch films and the interactions with the machinery, used for the wrapping and handling of round bales, have been considered for the design of this European Standard. However, it is difficult to simulate
22、 in laboratory conditions some parameters like leak tightness, oxygen permeability, temperature and the manner they interact. In order to obtain a high quality for silage it is very important to restrict unwanted microbiological activities to very low levels. Carbon dioxide producing processes can b
23、e suppressed by high partial pressure of CO2inside the bales. Aerobic processes are, of course, suppressed by low oxygen pressure. Consequently, the wrapped bale should be as gas tight as possible. Therefore this European Standard recommends using 6 layers of film as a minimum. This European Standar
24、d does not include as mandatory a test method for the determination of leak tightness on artificial bale. Nevertheless it is recommended for the manufacturers of stretch films to check this property near an appropriate testing laboratory. There are discussions regarding how the temperature inside th
25、e bale will influence how different types of “good“ and “bad“ microbiological activities will develop in forage. Although the film can be made of any colour, it is a fact that the pigmentation or colour itself will influence the temperature inside the bale, due to sun-radiation. Therefore, this Euro
26、pean Standard also includes a method for the determination of the solar reflectance of stretch films. EN 14932:2006 (E) 6 1 Scope This European Standard specifies the requirements for dimensional, mechanical and optical characteristics of stretch thermoplastic films for wrapping round bales used for
27、 outdoor ensiling of forage. This European Standard specifies classifications for durability and solar reflectance of stretch films for wrapping round bales. This European Standard specifies also test methods to check these requirements. This European Standard is applicable to white, black or colour
28、ed films based on polyethylene and/or ethylene copolymers. The range of film widths considered is from 250 mm up to 1 000 mm. NOTE 6 layers of stretch films, pre stretched up to 80 %, should be used for wrapping round bales. 2 Normative references The following referenced documents are indispensable
29、 for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2155-5, Aerospace series Test methods for transparent materials for aircraft glazing Part 5: Deter
30、mination of visible light transmission EN ISO 527-1, Plastics Determination of tensile properties Part 1: General principles (ISO 527-1:1993 including Corr 1:1994) EN ISO 527-3, Plastics Determination of tensile properties Part 3: Test conditions for films and sheets (ISO 527-3:1995) EN ISO 4892-2:2
31、006, Plastics Method of exposure to laboratory light sources Part 2: Xenon-arc lamps (ISO 4892-2:2006) EN ISO 6383-2, Plastics Film and sheeting Determinations of tear resistance Part 2: Elmendorf method (ISO 6383-2:1983) EN ISO 7765-1, Plastics film and sheeting Determination of impact resistance b
32、y the free-falling dart method Part 1: Staircase methods (ISO 7765-1:1988) ISO 4592, Plastics Film and sheeting Determination of length and width ISO 4593, Plastics Film and sheeting Determination of thickness by mechanical scanning ISO 9845-1, Solar energy Reference solar spectral irradiance at the
33、 ground at different receiving conditions Part 1: Direct normal and hemispherical solar irradiance for air mass 1,5 ISO 15105-2:2003, Plastics Film and sheeting Determination of gas-transmission rate Part 2: Equal-pressure method EN 14932:2006 (E) 7 3 Terms and definitions For the purposes of this d
34、ocument, the following terms and definitions apply. 3.1 width total width of the film when laid flat, given in millimetres 3.2 nominal width (W0) width declared by the manufacturer in millimetres 3.3 nominal thickness thickness of the film, as declared by the manufacturer, in micrometres (m) 3.4 len
35、gth of the film largest dimension of the film corresponding to the length of the un-winded roll, in metres 3.5 nominal length (L0) length of the film, as declared by the manufacturer, in metres 3.6 longitudinal direction of the film (MD) direction parallel to the length of the film corresponding to
36、the extrusion direction 3.7 transverse direction of the film (TD) direction parallel to the width (at right angles to the length) 3.8 core protrusion distance from the edge of the roll to the edge of the core, in millimetres 3.9 neck-in (Ni) shrinkage of the film in the transverse direction (TD) ind
37、uced by the stretching of the film in longitudinal direction (MD), in % (see 9.5) 3.10 tightening force force applied on the film after 10 min to maintain a tensile strain of a value of 50 %, in Newton (N) 4 Materials Stretch films for wrapping bales according this European Standard are usually manu
38、factured from: blends of low-density polyethylene (PE-LD) and linear low-density polyethylene (PE-LLD); ethylene vinyl acetate copolymers (EVAC) and their blends with PE-LD or PE-LLD; ethylene butyl acrylate copolymers (EBAK) and their blends with PE-LD or PE-LLD. EN 14932:2006 (E) 8 5 Solar reflect
39、ance The solar reflectance of stretch films is defined by the classes “High reflectance” and “Low reflectance”. This classification, given in Table 1, is depending of the value of solar reflectance measured on one layer of unstretched film according to Annex A. The class of solar reflectance shall b
40、e declared by the manufacturer. Table 1 Classification according to solar reflectance Class of film Solar reflectance Rs% High reflectance 28 Low reflectance 300 Annex E Total light transmission % 75 EN 2155-5 Coefficient of oxygen permeability acm /(m 24 h) 1 400 Annex A of ISO 15105-2:2003 aChecke
41、d on 6 layers of un-stretched film. EN 14932:2006 (E) 10 8.2 Requirement for appearance The edges of the reels shall be straight. The winding shall be without bubbles and wrinkles affecting film quality on the face of the roll. The film shall be homogeneous and free from visible defects which may af
42、fect the fitness for purpose of the stretch film: check by unrolling at least 2 m of the film and examining it against the light holding it tight at arms length. 9 Test methods 9.1 Determination of thickness The thickness of the single points and average thickness of the film shall be determined in
43、accordance with ISO 4593. The test is performed using one strip of film cut in transverse direction of the roll (TD). 9.2 Determination of width The width of the film shall be determined in accordance with ISO 4592. 9.3 Determination of core protrusion The core protrusion shall be measured on each s
44、ide of the roll. The value shall be expressed in mm. 9.4 Determination of length of film The length of the film shall be determined by unwinding the roll with a calibrated reel in contact continuously with its outside surface (see Figure 1). The calibrated reel is connected to a revolution counter.
45、The diameter of the calibrated reel is measured with an accuracy of 0,2 %. The roll is totally unwound at a speed of 100 m/min 10 m/min. The value of the length of the film is calculated with the following equation: l = n x d where l is the value of the length of the film, expressed in m; n is the n
46、umber of revolutions of the calibrated reel during the total unwinding of the roll; d is the value of the diameter of the calibrated reel, expressed in m. EN 14932:2006 (E) 11 Key 1 roll to be tested 2 calibrated reel with a revolution counter 3 collection reel Figure 1 Apparatus for the determinati
47、on of the length of the film 9.5 Determination of neck-in The neck-in shall be determined in accordance with Annex B. The result is expressed as the shrinkage in transverse direction in percentage of the original width. Ni= (W1 W2) / W1 x 100 where Niis the value of neck in expressed in %, W1is the
48、measure of width of the un-stretched film according to 9.2, W2is the measure of width of the stretched film on the bale. 9.6 Determination of tensile characteristics The tensile characteristics shall be determined according to EN ISO 527-1 and EN ISO 527-3 using five test pieces type 2, with a width
49、 of 10 mm, cut in each direction of the film, longitudinal direction (MD) and transversal direction (TD), at a testing speed of 500 mm/min. Calculate the arithmetic average value of the five measurements. The arithmetic average value shall fulfil the requirements of Table 3, as applicable. 9.7 Determination of impact resistance Impact resistance shall be determined in accordance with EN ISO 7765-1, method A. The test is performed on the film with the inside of the film, as seen from the reel, fac
