The Problem

Many mysterious problems in leather that manifest themselves at any stage of processing can originate from putrefaction of the raw material; grain damage, looseness, weakness, chrome soaps to name but a few. Needless to say, all result in downgrading or even rejection of leather. Bacteria are bad news!

The Problem
Fine breaks in the grain surface of leather, especially in the belly area, arising from the take off of the skin at the abattoir is commonly known at Butcher’s Strain, Strained Grain or Belly Strain. Providing the damage is slight and remains close to the belly edge of the skin, its impact is slight. However, if it is sufficiently severe, the resulting loss in useable leather can be significant. In severe cases the damage can extend right across the skin in an arc over the shoulder area.

Introduction

Defects are one of the biggest sources of non-conformity in leather production. Some of the defects are inherent in the live animal and the tanner is not able to measure the quality of their incoming raw material.

What is Bicast?

Bicast (or Bycast, Bykast, Baycast or Bikast as it is sometimes known) is essentially an alternative method of finishing a split leather. In cattle hides, the collagen fibres in the corium are much larger than they are in the grain. Therefore, when the leather has been split, the split surface will be very rough . If a conventional finish is sprayed to this rough surface, it will still appear very rough.

The problem

Tanners and users of vegetable tanned leather will almost certainly have come across annoying discolourations of their leather, the so-called 'ink' stains. These stains can vary in colour from dark grey through to inky black or dark green and the pattern can vary according to the source.

The problem

Yellowing of leather is a problem that has confounded our industry for a very long time. Obviously, pale and pastel shades will be affected most, but other colours are affected, just more difficult to see and will normally manifest itself in a change of colour, ie a blue leather will appear slightly greener if yellowing has occurred. All stages of the leather making process can be affected and even the final product such as footwear.

The problem

Sudden and unexplained problems with weakness are often reported to our laboratories. The tanner may complain that he has used the same process day after day with no problems, then all of a sudden a small percentage of a batch may have low tear strength or lastometer values.

The problem

It has been found that there are some contradictions in the definitions of aniline, semi-aniline and pigmented leather in the available literature. This has inevitably lead to some confusion within the industry, particularly over the description of semi-aniline leather.

The problem

In use, leather can be subjected to considerable stresses, eg during lasting it is heated to temperatures which can be in excess of 100°C and stretched with considerable force.

The problem

Hair slip occurs when the hair or wool in raw hides or skins has been sufficiently degraded by enzymes to allow it to be removed from the hide or skin with relative ease.

The problem

Problems due to changes in the colour of leather when exposed to light present themselves on a fairly regular basis and occur across a wide spectrum of leather articles. Most commonly poor lightfastness results in a fading of the colour intensity from dark to pale.

The problem

The problem

Acids are an essential ingredient in many parts of the leather making process. They are used as a preservative for part processed skins, eg pickled pelts, and to create the correct pH for chemical penetration and reaction to occur, eg penetration of chrome tanning agents.

The problem

One of the key advantages leather has over other materials is that it possesses great strength without losing its flexibility and porosity - few man made products can rival it!

The problem

Peeling of the finish during use is a frequent customer complaint, particularly in domestic upholstery leather . Sometimes the entire finish peels away from the leather surface, but more commonly it is an inter-coat adhesion problem.

The problem

Very prominent blood vessels in leather are not only unsightly but can also present some physical problems; they can sometimes present an area of weakness along which the leather constantly flexes, giving rise to irregular deep creases instead of a uniform small break.

The problem

As soon as a hide or skin is removed from the carcase, it is susceptible to bacterial attack. The bacteria penetrate into the skin via the exposed flesh surface where they can rapidly multiply. Under ideal conditions, a single bacterium can divide every 20 minutes and, therefore, within 24 hours will have multiplied to give a population of 4,000 million.

The Problem

Grain damage is probably one of the most common problems occurring in the tannery and the cost can be immense.

The issue

The problem

Like bacteria, mould spores are everywhere and most of the time they cause no harm. However, every now and again mould raises its ugly head and can cause untold damage. Not only is mould growth unsightly, it can be a health hazard.