DD234435A1

DD234435A1 - NON-ADHESIVE LIABILITY FOR PAPER SOCKET

Info

Publication number: DD234435A1
Application number: DD27295685A
Authority: DD
Inventors: Frans Steffers; Bernd Rothenhaeusser; Walter Winkler; Manfred Bunzel; Juergen Hauschild
Original assignee: Buna Chem Werke Veb
Priority date: 1985-02-01
Filing date: 1985-02-01
Publication date: 1986-04-02

Abstract

Die Erfindung betrifft ein nichtklebendes Haftmittel fuer Papiersaecke, das ein Verrutschen der gefuellten Saecke beim Transport auf Paletten verhindert, ohne beim Entladen zu Beschaedigungen der Saecke infolge dauerhafter Verklebung zu fuehren. Das erfindungsgemaesse Haftmittel ist eine maximal 7%ige waessrige alkalische Dispersion eines Butadien-Styren-Carbonsaeure-Copolymerisates, deren Viskositaet hoechstens 30 mPas betraegt.The invention relates to a non-adhesive adhesive for paper bags, which prevents slippage of the filled Saecke when transported on pallets, without leading to damage the Saecke during unloading due to permanent bonding. The adhesive according to the invention is a maximum of 7% aqueous alkaline dispersion of a butadiene-styrene-carboxylic acid copolymer whose viscosity is at most 30 mPas.

Description

embodiments

Für das neue Anwendungsgebiet von Haftmitteln auf Basis wäßriger Copolymerisate gibt es noch kein reproduzierbares Prüfverfahren, sodaß im Prinzip nur ein Eignungstest unter üblichen Verpackungs- und Transportbedingungen durchgeführt werden kann. Um trotzdem eine Vergleichsmöglichkeit zu haben, wurde folgende Prüfung durchgeführt:For the new field of application of adhesives based on aqueous copolymers, there is still no reproducible test method, so that in principle only a suitability test under normal packaging and transport conditions can be performed. In order to still have a possibility of comparison, the following test was carried out:

Aus Papiersäcken wurden Stücke von 50 x 100 mm geschnitten. Da die gebräuchlichsten Papiersäcke aus 4 Schichten Papier bestehen, wurden 4 Probestücke aufeinandergelegt, darauf wurde mit einem 2cm breiten Pinsel ein Haftmittelstreifen gestrichen und darauf 4 andere Probestücke gelegt. Das ganze Paket, also 8 Streifen, wurde 24 Stunden mit einem 10 kg-Gewicht belastet. Nach 24 Stunden wurden die 4 bestrichenen Papiere von den 4 anderen abgezogen, wozu also eine geringe Kraftanwendung erforderlich war. Hiernach wurde festgestellt, ob die Haftung so stark gewesen war, daß bei der Trennung Papierfasern aus den anderen nicht bestrichenen 4 Probestücken mitgerissen wurden. Ferner wurde bei allen Papierlagen geprüft, ob das Haftmittel durch eine oder mehrere Schichten durchgeschlagen war.From paper sacks pieces of 50 x 100 mm were cut. Since the most common paper sacks consist of 4 layers of paper, 4 specimens were stacked on top of each other, a strip of adhesive was spread over a 2cm wide brush and 4 other specimens placed on top. The whole package, ie 8 strips, was loaded with a 10 kg weight for 24 hours. After 24 hours, the 4 coated papers were peeled off from the 4 others, which required little application of force. Afterwards it was determined whether the adhesion had been so strong that with the separation paper fibers from the other uncoated 4 specimens were entrained. In addition, all paper layers were tested to see if the adhesive had passed through one or more layers.

Zum Vergleich mit dem Stand der Technik wurde eine handelsübliche Dispersion auf Basis eines Copolymerisats von Polyvinylacetat/Acrylat herangezogen, die z. Z. als Haftmittel eingesetzt wird. Da dieses Produktsich nach einigen Stunden in 2 Schichten trennte, mußte im Gegensatz zum erfindungsgemäßen Produkt vor jedem Versuch das Vergleichsprodukt intensiv gerührt werden, ehe ein Streichversuch durchgeführt wurde.For comparison with the prior art, a commercial dispersion based on a copolymer of polyvinyl acetate / acrylate was used, the z. Z. is used as an adhesive. Since this product separated after 2 hours in 2 layers, in contrast to the product according to the invention before each experiment, the comparison product had to be stirred intensively before a coating test was carried out.

Beispiel 1 beschreibt das erfindungsgemäße Haftmittel, Beispiel 2iind3 dienen dem Vergleich mit dem Stand der Technik.Example 1 describes the adhesive according to the invention, Example 2iind3 serve for comparison with the prior art.

Beispiel 1 (erfindungsgemäß)Example 1 (according to the invention)

Gemäß DD-PS 80546 wurde ein Latex aus 38Gew.-% Butadien, 2Gew.-% Methacrylsäure, 0,5Gew.-% Fumarsäure und 59,5Gew.-% Styren hergestellt. Die Viskosität einer 6%igen wäßrigen Lösung dieses Copolymerisats betrug nach der pH-Wert-Einstellung mit Natronlauge auf 7,9 24mPa · s.According to DD-PS 80546, a latex of 38% by weight of butadiene, 2% by weight of methacrylic acid, 0.5% by weight of fumaric acid and 59.5% by weight of styrene was prepared. The viscosity of a 6% aqueous solution of this copolymer was after the pH adjustment with sodium hydroxide to 7.9 24mPa · s.

Beispiel 2 (nicht erfindungsgemäß)Example 2 (not according to the invention)

Mit dem Latex aus Beispiel 1 wurde eine 9%ige Lösung (wäßrig) hergestellt.With the latex from Example 1, a 9% solution (aqueous) was prepared.

Beispiel 3 (Stand der Technik) ,Example 3 (prior art),

Eine handelsübliche wäßrige Copoiymerisatdispersion, z.Z. als Antirutschrrnttel eingesetzt, wird mit einem Feststoffgehalt von 5% als Vergleichsmuster herangezogen.A commercial aqueous copolymer dispersion, z. used as anti-friction Schrnttel, is used with a solids content of 5% as a reference sample.

Das Produkt war eine wäßrige Dispersion eines PVAc-Acrylat-Copolymers.The product was an aqueous dispersion of a PVAc-acrylate copolymer.

Wie beschrieben, wurde der Labortest mit Papiersackmaterial durchgeführt. Die Ergebnisse sind aus Tabelle 1 zu entnehmen.As described, the laboratory test was carried out with paper bag material. The results are shown in Table 1.

Table 1

Haftmittel aus Bsp. 12 3Adhesive from Ex. 12 3

Haftung , ja ja ja bei Trennung Papier-Fasern mitgerissen nein ja ja Durchgeschlagen nein nein jaAdhesion, yes yes yes, if paper fibers were separated, no Yes, yes, no, no

Claims

Invention claim:

Non-sticky adhesive for paper sacks, which are transported filled on pallets, based on aqueous alkaline Butadiencopolymerisatlatices, characterized in that the solids content in the adhesive is at most 7 wt .-%, the viscosity is not above 3OmPa-S, the Butadienanteil in the copolymer at most 39Gew .-% and the remaining monomers are styrene and unsaturated carboxylic acids.

Field of application of the invention

The invention relates to a non-adhesive adhesive for solidifying filled paper bags, which are transported stacked on pallets. The adhesive sufficiently connects the bags to be transported to prevent them from slipping or falling. The sacks can be separated from each other without forcing them without tearing.

Characteristic of the known technical solutions

The securing of filled paper sacks during transport against slipping is achieved by using adhesives.

Such adhesives, which are prepared on the basis of high polymer solutions with plasticizers, fillers, extenders and other auxiliaries, serve to join the same or different materials.

For economic and ecological reasons, such adhesives are becoming increasingly important, which stick together without releasing volatile constituents.

Also, aqueous dispersions of water-insoluble organic polymers belong to this class of adhesives. Besides the use of natural latex, described i.a. Noble "Latex in Industry", Rubber Age, New York, 2nd, edn 1953. Synthetic latexes have become increasingly popular as specialty adhesives in recent years, with no clear distinction between elastic thermoplastics, thermoplastics, and synthetic rubbers in the adhesives industry made.

Sometimes adhesives consist of combinations or mixtures of different polymers. The class of polyvinyl adhesives includes polyvinyl esters, ethers, acetals, alcohols and polystyrenes. Adhesives based on polystyrene copolymerisates are known in particular as solution adhesives. You will u.a. their use in the form of aqueous dispersions or emulsions is not known. The copolymers of styrene and butadiene in a ratio of about 50:50 are described i.a. used as a binder in adhesive compounds for the bonding of leather and rubber. In this case, the so-called destabilization of the emulsion is used as a technology, after which sticky surfaces are formed at the points to be bonded, which, connected to one another, make the bonding possible. Copolymers with 60% or more styrene content are used only as hot melt adhesives.

Solution adhesives based on acrylonitrile / butadiene are u. a. by G.H. Garlick in Nitrile Rubber and Latices, Rubber Plastic Age, 42 (10) 1961, 1235, which discloses butadiene / acrylic acid or methacrylic acid in Ind. Eng. Chem., 44 (7) 1952, 1600. It is surprising that such. B. from mixtures for egg processing by W. Kleemann, VEB German publishing house for basic industry Leipzig, I.Auflage 1982, it can be seen for butadiene copolymers still only solvents are used.

It is the demand of economics and ecology to use more economical adhesives with higher environmental friendliness. So it is also logical that aqueous dispersions and emulsions with properties that could previously be achieved only by adhesive solutions are developed to an ever greater extent.

However, the broader the field of application of aqueous dispersions or emulsions, the more specific and targeted are the requirements for the adhesive. It slowly turns out that so-called universal adhesives can be treated with solvents such as e.g. Contact adhesive, can not be replaced by a universal adhesive on an aqueous basis and practically a specific polymer is needed for each material to be bonded.

Non-adhesive adhesives based on aqueous copolymers as a safeguard against the slipping or falling of filled paper sacks of pallets during transport, which meet the requirements of economy and ecology, are not known.

Object of the invention #

The aim of the invention is to secure with the help of a suitable adhesive filled paper bags especially during transport on pallets against slipping and falling. The adhesive should be aqueous-based, contain no organic solvent, and be easy to apply. Damage to the bags by tearing as a result of gluing together should be avoided.

Explanation of the essence of the invention

The invention has for its object to develop a non-adhesive adhesive for paper sacks, through which the above requirements are ensured.

The object is achieved by an adhesive based on aqueous alkaline Butadiencopolymerisatlatices, characterized in that the solids content max. 7% by weight, the butadiene content in the copolymer max. 39 wt .-%, the remaining monomers are styrene and unrjp-saturated carboxylic acids and the viscosity is not above 3OmPa · s.

The preparation of the aqueous butadiene copolymers is carried out according to known prior art, such as. B. in OD: S 80546 or DD-PS 148226 described. However, it is absolutely necessary to take into account the quantities according to the invention.

Smaller deviations, which are outside the aforementioned limits of invention, surprisingly lead to a huge decrease in the desired properties, namely to protect the bags during transport against chutes without sticking together, so that a discharge of the bags can be done without damage.

Since the adhesives according to the invention are thin, their maximum viscosity should not exceed 3OmPa s, application can be done with the brush.

Heating is also omitted, as it is e.g. require the hot melt adhesives, which z.Z. mainly used for securing the paper sacks during transport. It is further surprising that other aqueous polymer dispersions, which are already used as an adhesive anyway, such as. As PVac dispersions, at the low Feststoffkonzentratior.on invention are so unstable that they precipitate after a few hours. Attempts to stabilize them with a higher emulsifier content failed because too much foaming makes processing and action more difficult.