ISSN:0894-3214    

DOI:10.1002/pts.2770010202

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe effect of relative humidity on the diffusion of toluene vapour through a multi‐layer coextrusion film structure containing moisture sensitive hydrophilic barrier layers (nylon and EVAL) was evaluated. Two experimental test methods were employed. In Method I, the effect of relative humidity on the diffusion of toluene vapour was evaluated, where the test film was preconditioned to a fixed water activity prior to test. In Method II, the effect of water vapour as a co‐permeant was evaluated. Studies carried out by Method I showed the concentration dependency of the diffusion process and the importance of relative humidity on the diffusion of organic vapour through barrier structures. Water vapour was found to exhibit strong interactive effects with the moisture sensitive polymer layers of the laminate, which resulted in an increase in the diffusion of toluene vapour through the barrier structure. When the effect of water vapour as a co‐permeant was evaluated (Method II), the direction of permeation (i.e. surface exposed to high relative humidity and vapour concentration) markedly influenced the resultant barrier prope

ISSN:0894-3214    

DOI:10.1002/pts.2770010203

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper considers the factors that will influence successful adhesive bonding to carton‐boards. Although the paper assumes the use of carton‐board within the packaging industry, the majority of the arguments may be applied to other bonding applications.The commonest adhesive types used within the packaging industry for carton‐boards are PVA‐type emulsion and hot‐melts. Other adhesives used will include animal glues, starches and dextrines, acrylics etc. Although these adhesives vary considerably in properties they share the majority of requirements for successful bonding.The paper firstly considers bond structure and the basic modes of bond failure. It is surprising how often these are misunderstood or ignored when bonding problems occur. An inspection of the precise nature of a bond failure often suggests the cause of the problem, and at least eliminates a number of possible causes.The paper then discusses the properties required of boards, board surfaces (be they printed, varnished, coated or otherwise) and adhesives for the successful manufacture of bonds. Techniques for evaluating trial bond performance and, finally, the need for good 'housekeeping' are c

ISSN:0894-3214    

DOI:10.1002/pts.2770010204

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe paper reports a recent data base produced for, and available to National Packaging Centres, in developing countries. The ITC in Geneva hold the material which is updated regularly. It should enable enquirers to ascertain details of the equipment they require and to choose between several alternatives.

ISSN:0894-3214    

DOI:10.1002/pts.2770010205

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAlthough the tensile strength or bending stiffness of paperboard is high, in general the material possesses good fold, creasing or scoring properties. Both crease and fold resistance are surprisingly low, as is the rate of crack propagation along the deformation lines. The background to this characteristic is explained.It is shown experimentally that the folding resistance before and after creasing,MBandM'respectively, are strongly correlated with the (in plane) compression strength of the material, approximately according toMB˜τBC· τ2andM'/MB˜ ϵBc, wheretis the board thickness, τBCand ϵBcare the compression breaking stress and strain respectively.The strength in compression is several times lower than in tension, both in terms of stress and strain. Consequently, the manner in which the material yields, both in folding and in creasing fracture, originates from the compression regions, i.e. the concave parts of the deformation zone. The tension level at this time may only be 30–50% of its maximum. The breaking limit in tension is reached far later than in compression, and can effectively be ignored.Combined shear stresses (out of plane) of various magnitudes, applied during folding, do not change the relationships found. The material is insensitive to shear stress at least up to folding angles of 90°.Crack propagation along the cut, folded or creased lines is directly related to the in‐plane compression strength of the material, approximately according to l˜Lc−1(τBC/T87‐)2, where /is the crack length, τeris the tension breaking stress and τc‐1is the brittleness characterized by the critical tensile span of the material, Lc.The rate of crack propagation is greatly reduced in comparison to materials with more equal compression and tension strength and can be as little as 75 or 90%, due to the actual strength ratio. Additionally, paperboard has a relatively high critical span length, Lc, of the same order as that of various synthetic fibre composites, which reduces crack propagation even further.It is necessary to keep the compression strength as low as possible in the development of paperboard; if compression strength needs to be raised, e.g. for end‐usability, tensile strength also needs to be increased, or brittleness reduced, at least in the outer layers of the material. If these adjustments are not made, the properties that make for good convertibility are degraded, according

ISSN:0894-3214    

DOI:10.1002/pts.2770010206

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe manner in which recycling of plastic packaging is developing in the USA is outlined and the probable changes in the next decade are discussed. Suggestions as to how packaging professions should deal with the subject are made.

ISSN:0894-3214    

DOI:10.1002/pts.2770010207

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe principle of uniformity in national and international transport regulations has now been widely recognized and implemented. Most features of the regulations are now fully operational e.g. in respect of classification, permitted packagings and maximum quantities, labelling etc. So far as packaging standards are concerned, 1990 is scheduled as the end of the transitional period. The major problem anticipated, that of the vast numbers of combination packagings needing testing and certifying, has hopefully been reduced to a level consistent with safety by the development of the UNlimited quantityprovisions, their adoption in the IMDG Code and the similar provisions in RID/ADR. The outstanding questions relate to air transport. Non‐specification packagings have been acceptable in air transport under the transitional packaging arrangements since the ICAO Technical Instructions came into effect in 1983/84: these are often far larger in size than those covered in Chapter 15 of the UN Recommendations. As far as is known, the use of these non‐specification packagings has not given rise to problems in air transport. It is hoped that the ICAO Dangerous Goods Panel will adopt practicallimited quantityprovisions from 31 December 1

ISSN:0894-3214    

DOI:10.1002/pts.2770010208

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770010209

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770010210

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770010201

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY